゙ノメノネタテノ モタフトンヘノトメマ ヘタロメマフトチノモ ヘヨモ眤

(i) フマヘマツメタラノトチノ

  1. Some singular boundary value problems for ordinary differential equations. (Russian) Tbilisi University Press, Tbilisi, 1975.

  2. Boundary value problems for systems of ordinary differential equations. (Russian) Itogi Nauki Tekh., Ser. Sovrem. Probl. Mat., Novejshie Dostizh. 30 (1987), 3-103; English transl.: J. Sov. Math. 43 (1988), No. 2, 2259-2339.

  3. Singular boundary value problems for second order ordinary differential equations (with B. L. Shekhter). (Russian) Itogi Nauki Tekh., Ser. Sovrem. Probl. Mat., Novejshie Dostizh. 30 (1987), 105-201; English transl.: J. Sov. Math. 43 (1988), No. 2, 2340-2417.

  4. Asymptotic properties of solutions of nonautonomous ordinary differential equations (with T. Chanturia). (Russian) Nauka, Moscow, 1990.

  5. Asymptotic properties of solutions of nonautonomous ordinary differential equations (with T. Chanturia). Kluwer Academic Publishers, Dordrecht-Boston-London, 1993.

  6. On multi-point boundary value problems for systems of functional differential and difference equations (with Sh. Gelashvili). Mem. Differential Equations Math. Phys. 5 (1995), 1-113.

  7. Initial and boundary value problems for systems of ordinary differential equations, I. (Russian) Metsniereba, Tbilisi, 1997.

  8. Boundary value problems for systems of linear ordinary differential equations. (Czech) Masaryk University, Brno, 1997.

  9. Boundary value problems for systems of linear functional differential equations (with B. Pů杪). Masaryk University, Brno, 2003.

(ii) モタフトンヘノトメマ モヤタヤノトチノ

  1. On the oscillation of solutions of some ordinary differential equations. (Russian) Dokl. Akad. Nauk SSSR 144 (1962), No. 1, 33-36; English transl.: Sov. Math., Dokl. 3 (1962), 649-652.

  2. On oscillation conditions for solutions of the equation . (Russian) Časop. Pěstov. Mat. 87 (1962), No. 4, 492-495.

  3. On asymptotic properties of solutions of the equation . (Russian) Soobshch. Akad. Nauk Gruz. SSR 30 (1963), No. 2, 129-136.

  4. On the oscillation of solutions of the equation . (Russian) Mat. Sb. 65 (1964), No. 2, 172-187.

  5. On the asymptotic representation of solutions of linear differential equations. (Russian) Trudy Tbiliss. Univ. Mat. Mekh. Astronom. 102 (1964), 149-167.

  6. On nonoscillatory solutions of the equation . (Russian) Soobshch. Akad. Nauk Gruz. SSR 35 (1964), No. 1, 15-22.

  7. A note on the boundedness of solutions of differential equations. (Russian) Trudy Tbiliss. Univ. Mat. Mekh. Astronom. 110(1965), 103-108.

  8. Concerning the oscillation of solutions of nonlinear differential equations. (Russian) Differentsial地ye Uravneniya 1 (1965), No. 8, 995-1006; English transl.: Differ. Equations 1 (1965), 773-782.

  9. Comparison lemma and the question of uniqueness of solutions of the Cauchy problem for ordinary differential equations. (Russian) Soobshch. Akad. Nauk Gruz. SSR 39 (1965), No. 3, 513-518.

  10. On the Cauchy problem for ordinary differential equations with singularity. (Russian) Soobshch. Akad. Nauk Gruz. SSR 37 (1965), No. 1, 19-24.

  11. On the Cauchy problem for singular systems of ordinary differential equations. (Russian) Differentsial地ye Uravneniya 1(1965), No. 10, 1271-1291; English transl.: Differ. Equations 1 (1965), 995-1011.

  12. Asymptotic properties of solutions of a nonlinear differential equation of Emden-Fowler type. (Russian) Izv. Akad. Nauk SSSR. Ser. Mat. 29(1965), No. 5, 965-986.

  13. On a priori estimates of  derivatives of bounded functions satisfying second order differential inequalities. (Russian) Differentsial地ye Uravneniya 3 (1967), No. 7, 1043-1052; English transl.: Differ. Equations 3 (1967), 541-546.

  14. A note on the oscillation of solutions of the equation . (Russian) Časop. Pěstov. Mat. 92 (1967), No. 3, 343-350.

  15. Some remarks on the solutions of the equation  (with D. V. Izjumova). (Russian) Differentsial地ye Uravneniya 4 (1968), No. 4, 589-605; English transl.: Differ. Equations 4 (1968), 302-310.

  16. On the monotone solutions of nonlinear n-th order ordinary differential equations. (Russian) Dokl. Akad. Nauk SSSR 181 (1968), No. 5, 1054-1057; English transl.: Sov. Math., Dokl. 9 (1968), 980-983.

  17. On some singular boundary value problems for nonlinear second order ordinary differential equations. (Russian) Differentsial地ye Uravneniya 4 (1968), No. 10, 1753-1773; English transl.: Differ. Equations 4 (1968), 901-910.

  18. On periodic solutions of nonlinear second order differential equations. Proc. of IV Conf. on Nonlinear Oscillations. Academia, Prague, 1968, 175-180.

  19. On non-negative non-increasing solutions of non-linear second order differential equations. Ann. Mat. Pura ed Appl. 81 (1969), 169-192.

  20. On the singular problem of Nicoletti. (Russian) Dokl. Akad. Nauk SSSR 86 (1969), No. 4, 769-772; English transl.: Sov. Math., Dokl. 10 (1969), 663-666.

  21. On nonoscillation conditions for singular linear second order differential equations. (Russian) Mat. Zametki 6 (1969), No. 5, 633-639.

  22. On monotone solutions of nonlinear n-th order ordinary differential equations. (Russian) Izv. Akad. Nauk SSSR. Ser. Mat. 33 (1969), No. 6, 1373-1398; English transl.: Math. USSR, Izv. 3 (1969), 1293-1317.

  23. On a singular two-point boundary value problem. (Russian) Differentsial地ye Uravneniya 5 (1969), No. 11, 2002-2016; English transl.: Differ. Equations 5 (1969), 1493-1504.

  24. On a singular multi-point boundary value problem. Ann. Mat. Pura  Appl. 86 (1970), 367-399.

  25. On oscillatory solutions of nonlinear ordinary differential equations. (Russian) Proc. of 5-th Intern. Conf. on  Nonlinear Oscillations, 1, Kiev, 1970, 293-298.

  26. On a singular boundary value problem. J. Math. Anal. Appl. 30 (1970), No. 3, 475-489.

  27. On the existence and uniqueness of solutions of singular boundary value problem. Fasc. Math. (1970), No. 5(74), 5-16.

  28. On a singular boundary value problem for the n-th order ordinary differential equation. (Russian) Dokl. Akad. Nauk SSSR 192 (1970), No. 5, 973-975; English transl.: Sov. Math., Dokl. 11 (1970), 755-757.

  29. Remarks on the asymptotic behaviour of solutions of the equation  (with T. A. Chanturia). (Russian) Differentsial地ye Uravneniya 6 (1970), No. 6, 115-117; English transl.: Differ. Equations 6 (1970), 855-857.

  30. On some nonlinear boundary value problems, I. (Russian) Bull. Inst. Politehn. Iasi 16 (1970), No. 3-4, 57-65.

  31. On a boundary value problem for a system of two differential equations. (Russian) Proc. Tbilisi Univ. 1(137) A (1971), 77-87.

  32. On a boundary value problem for the system of ordinary differential equations (with M. A. Kakabadze). (Russian) Differentsial地ye Uravneniya 7 (1971), No. 9, 1611-1616; English transl.: Differ. Equations 7 (1971), 1225-1229.

  33. On periodic solutions of the system of ordinary differential equations with singularities. (Russian) Dokl. Akad. Nauk SSSR 198 (1971), No. 2, 286-289; English transl.: Sov. Math., Dokl. 12 (1971), 777-781.

  34. On a singular boundary value problem  for an n-th order ordinary differential equation. (Russian) Trudy Inst. Prikl. Mat. Tbiliss. Univ. 3 (1972), 187-206.

  35. On some nonlinear boundary value problems, II. (Russian) Bull. Inst. Politehn. Iasi 18 (1972), No. 3-4, 95-107.

  36. Oscillatory solutions for a generalized sublinear second order differential equation (with J. W. Heidel). Proc. Amer. Math. Soc. 38 (1973), No. 1, 80-82.

  37. On oscillation conditions for  solutions of nonlinear ordinary differential equations, I. (Russian) Differentsial地ye Uravneniya 10 (1974), No. 8, 1387-1399; English transl.: Differ. Equations 10 (1974), 1073-1082.

  38. On oscillation conditions for solutions of nonlinear ordinary differential equations, II. (Russian) Differentsial地ye Uravneniya 10 (1974), No. 9, 1586-1594; English transl.: Differ. Equations 10 (1974), 1224-1230.

  39. Concerning the solvability of nonlinear two-point boundary value problems (with N. R. Lezhava). (Russian) Mat. Zametki 16 (1974), No. 3, 479-490; English transl.: Math. Notes 16 (1974), 873-880.

  40. Concerning nonoscillatory singular linear second order differential equations (with N. V. Gogiberidze). (Russian) Differentsial地ye Uravneniya 10 (1974), No. 11, 2064-2067; English transl.: Differ. Equations 10 (1974), 1598-1601.

  41. On some nonlinear two-point boundary value problems (with N. R. Lezhava). (Russian) Differentsial地ye Uravneniya 10 (1974), No. 12, 2147-2161; English transl.: Differ. Equations 10 (1974), 1660-1671.

  42. On a singular problem of Cauchy-Nicoletti. Ann. Mat. Pura  Appl. 104 (1975), 151-175.

  43. On the modified problem of Cauchy-Nicoletti. Ann. Mat. Pura Appl. 104 (1975), 177-186.

  44. On some boundary value problems for a system of ordinary differential equations (with B. Pů杪). (Russian) Differentsial地ye Uravneniya 12 (1976), No. 12, 2139-2148; English transl.: Differ. Equations 12 (1976), 1493-1500.

  45. On a nonlinear boundary-value problem (with N. R. Lezhava). Function Theoretic Methods in Diff. Equations. Pitman Publ., London, 1976, 259-276.

  46. On the periodic boundary value problem for the two-dimensional differential system. (Russian) Differentsial地ye Uravneniya 13 (1977), No. 6, 996-1007; English transl.: Differ. Equations 13 (1977), 685-694.

  47. On oscillatory and monotone solutions of ordinary differential equations. Arch. Math. (Brno) 14 (1978), No. 1, 21-44.

  48. On the solvability of a nonlinear Kneser type problem (with I. Rachůnkov). (Russian) Differentsial地ye Uravneniya 15 (1979), No. 10, 1754-1765; English transl.: Differ. Equations 15 (1980), 1248-1256.

  49. On a certain nonlinear problem for two-dimensional differential systems (with I. Rachůnkov). Arch. Math. (Brno) 15 (1980), No. 1, 15-38.

  50. On asymptotic behaviour of solutions of nonlinear non-autonomous ordinary differential equations. Qual. Theory Differ. Equations, V. 1, Amsterdam e.a., 1981, 507-554.

  51. On strongly increasing solutions of nonlinear ordinary differential equations (with G. G. Kvinikadze). Ann. Math. Pura Appl. (4) 130 (1982), 67-87.

  52. On some singular boundary-value problems for ordinary differential equations. Equadiff 5, Proc. 5 Czech. Conf. Differ. Equations and Appl., Teubner Verlagsgesselschaft, Leipzig, 1982, 174-178.

  53. On the solvability of the Vall馥-Poussin problem. (Russian) Differentsial地ye Uravneniya 19 (1983), No. 9, 1648-1649.

  54. On numerical solution of two-point boundary value problems for second order ordinary differential equations (with G. S. Tabidze). (Russian) Trudy Inst. Prikl. Mat. im. I. N. Vekua 14 (1983), 69-127.

  55. On vanishing at infinity solutions of ordinary differential equations. Czechoslovak Math. J. 33 (1983), No. 4, 613-646.

  56. On certain boundary-value problems for second-order linear ordinary differential equations with singularities (with A. G. Lomtatidze). J. Math. Anal. Appl. 101 (1984), No. 2, 325-347.

  57. On two-point boundary value problems for systems of nonlinear ordinary differential equations. (Russian) IX Intern. Conf. in Nonlinear Oscillations, 1, Naukova Dumka, Kiev, 1984, 168-173.

  58. On the stability of the set of solutions of nonlinear boundary value problems (with D. G. Bitsadze). (Russian) Differentsial地ye Uravneniya 20 (1984), No. 9, 1495-1501; English transl.: Differ. Equations  20 (1984), 1073-1078.

  59. On the behaviour of solutions of higher order ordinary differential equations in the neighbourhood of a singular point. (Russian) Differentsial地ye Uravneniya 20 (1984), No. 10, 1703-1709; English transl.: Differ. Equations 20 (1984), 1216-1221.

  60. On a multi-point boundary value problem for systems of ordinary differential equations. Trudy Tbiliss. Univ. 259 (1984), 110-121.

  61. On bounded and periodic solutions of linear higher order differential equations. (Russian) Mat. Zametki 37 (1985), No. 1, 48-62; English transl.: Math. Notes 37 (1985), 28-36.

  62. On a priori estimates of solutions of nonlinear higher order differential inequalities. (Russian) Differentsial地ye Uravneniya 21 (1985), No. 2, 198-213; English transl.: Differ. Equations 21 (1985), 136-149.

  63. On the solvability of the Vall馥-Poussin problem. (Russian) Differentsial地ye Uravneniya 21 (1985), No. 3, 391-398; English transl.: Differ. Equations 21 (1985), 249-255.

  64. On oscillatory properties of a class of differential equations with deviating argument (with D. V. Izjumova). (Russian) Differentsial地ye Uravneniya 21 (1985), No. 4, 588-596; English transl.: Differ. Equations 21 (1985), 384-391.

  65. On periodic solutions of systems of nonautonomous ordinary differential equations. (Russian) Mat. Zametki 39 (1986), No. 4, 562-575; English transl.: Math. Notes 39 (1986), 308-315.

  66. On a boundary value problem with a condition at infinity for higher order ordinary differential equations. (Russian) Trudy Vsesojuznogo Simpoziuma po Diff. Uravnenijam v Chastnykh Proizvodnykh, Tbilis. Univ. Press, Tbilisi, 1986, 91-105.

  67. On boundary value problems for higher order ordinary differential equations with singularities. (Russian) Uspekhi Mat. Nauk 41 (1986), No. 4, 166-167.

  68. On some boundary value problems for systems of nonlinear ordinary differential equations. Equadiff 7, Proceedings of the Conference held in Prague, 1989. Teubner Verlagsgessellschaft, Leipzig, 1990, 37-46.

  69. On the Kneser problem for functional differential equations (with D. I. Chichua). (Russian) Differentsial地ye Uravneniya 27 (1991), No. 11, 1879-1892; English transl.: Differ. Equations 27 (1991), No. 11, 1322-1335.

  70. An oscillation criterion for a class of ordinary differential equations. (Russian) Differentsial地ye Uravneniya 28 (1992), No. 2, 207-219; English transl.: Differ. Equations 28 (1992), No. 2, 180-190.

  71. On the two-point boundary value problems for systems of higher order ordinary differential equations with singularities (with G. Tskhovrebadze). Georgian Math. J. 1 (1994), No. 1, 31-45.

  72. On some properties of solutions of second order linear functional differential equations. Georgian Math. J. 1 (1994), No. 5, 487-494.

  73. On asymptotic properties of solutions of third order linear differential equations with deviating arguments. Arch. Math. (Brno) 30 (1994), No. 1, 59-72.

  74. On some boundary value problems with integral conditions for functional differential equations (with D. Chichua). Georgian Math. J. 2 (1995), No. 2, 165-188.

  75. On proper oscillatory and vanishing at infinity solutions of differential equations with a deviating argument (with D. Chichua). Georgian Math. J. 2 (1995), No. 4, 395-418.

  76. Concerning the uniqueness of solution of the Cauchy problem for functional differential equations (with Z. Sokhadze). (Russian) Differentsial地ye Uravneniya 31 (1995), No. 12, 1977-1988;  English transl.: Differ. Equations 31 (1995), No. 12, 1947-1958.

  77. Existence and continuability of solutions of the initial value problem for the system of singular functional differential equations (with Z. Sokhadze). Mem. Differential Equations Math. Phys. 5 (1995), 127-130.

  78. On solvability of functional equations in the space of continuous vector functions. Mem. Differential Equations Math. Phys. 6 (1995), 109-112.

  79. On asymptotic behaviour of solutions of second order linear differential equations (with Z. Do嗟a). Mem. Differential Equations Math. Phys. 6 (1995), 130-133.

  80. On the singular Cauchy problem for systems of linear ordinary differential equations. (Russian) Differentsial地ye Uravneniya 32 (1996), No. 2, 215-223; English transl.: Differ. Equations 32 (1996), No. 2, 173-180.

  81. On the correctness of Cauchy problem for the linear differential system on an infinite interval. Georgian Math. J. 3 (1996), No. 5, 475-484.

  82. On a certain singular boundary value problem for linear differential equations with deviating arguments (with B. Pů杪). Czechoslovak Math. J. 47 (1997), No. 2, 233-244.

  83. On boundary value problems for systems of linear functional differential equations (with B. Pů杪). Czechoslovak Math. J. 47 (1997), No. 2, 341-373.

  84. On the Vall馥-Poussin problem for singular differential equations with deviating arguments (with B. Pů杪). Arch. Math. (Brno) 33 (1997), No. 1-2, 127-138.

  85. On periodic solutions of systems of linear functional differential equations (with B. Pů杪). Arch. Math. (Brno) 33 (1997), No. 3, 197-212.

  86. On the Cauchy problem for singular evolution functional differential equations (with Z. Sokhadze). (Russian) Differentsial地ye Uravneniya 33 (1997), No. 1, 48-59; English transl.: Differ. Equations 33 (1997), No. 1, 47-58.

  87. Conti-Opial type theorems for systems of functional differential equations (with B. Pů杪). (Russian) Differentsial地ye Uravneniya 33 (1997), No. 2, 185-194; English transl.: Differ. Equations 33 (1997), No. 2, 184-193.

  88. On singular functional differential inequalities (with Z. Sokhadze). Georgian Math. J. 4 (1997), No. 3, 259-278.

  89. On global solvability of the Cauchy problem for singular functional differential equations (with Z. Sokhadze). Georgian Math. J. 4 (1997), No. 4, 355-372.

  90. On periodic solutions of first order nonlinear differential equations with deviating arguments. Mem. Differential Equations Math. Phys. 10 (1997), 134-137.

  91. On the solvability of boundary value problems for systems of nonlinear differential equations with deviating arguments (with B. Pů杪). Mem. Differential Equations Math. Phys. 10 (1997), 157-161.

  92. On systems of ordinary differential equations and differential inequalities with multi-point boundary conditions. (Russian) Differentsial地ye Uravneniya 33 (1997), No. 5, 646-652; English transl.: Differ. Equations 33 (1997), No. 5, 649-655.

  93. On boundary value problems for functional differential equations (with B. Pů杪). Mem. Differential Equations Math. Phys. 12 (1997), 106-113.

  94. On the solvability of nonlinear boundary value problems for functional differential equations (with B. Pů杪). Georgian Math. J. 5 (1998), No. 3, 251-262.

  95. On existence of proper oscillatory solutions of advanced differential equations (with I. P. Stavroulakis). (Russian) Differentsial地ye Uravneniya 34 (1998), No. 6, 751-757; English transl.: Differ. Equations 34 (1998), No. 6, 748-754.

  96. On the structure of the set of solutions of the weighted Cauchy problem for evolution singular functional differential equations (with Z. Sokhadze). Fasc. Math., 1998, No. 28, 71-92.

  97. On vanishing at infinity solutions of second order linear differential equations with advanced arguments (with Z. Do嗟a). Funkcial. Ekvac. 41 (1998), No.2, 189-205.

  98. On the oscillation of solutions of higher order Emden-Fowler advanced differential equations (with I. P. Stavroulakis). Appl. Anal. 70 (1998), No. 1-2, 97-112.

  99. Concerning the solvability of two-point singular boundary value problems. (Russian) Uspekhi Mat. Nauk 53 (1998), No. 4, 153.

  100. On periodic solutions of nonlinear functional differential equations (with B. Pů杪). Georgian Math. J. 6 (1999), No. 1, 47-66.

  101. On periodic solutions of higher order nonautonomous ordinary differential equations (with T. Kusano). Differentsial地ye Uravneniya 35 (1999), No. 1, 72-78; English transl.: Differ. Equations 35 (1999), No. 1, 71-77.

  102. On boundedness and stability of solutions of second order linear differential equations with advanced arguments (with Z. Do嗟a). Adv. Math. Sci. Appl. 9 (1999), No. 1, 1-24.

  103. On nonnegative solutions of nonlinear two-point boundary value problems for two-dimensional differential systems with advanced arguments (with  N. Partsvania). E. J. Qualitative Theory of Diff. Equ., 1999, No. 5, 1-22.

  104. On periodic solutions of nth order ordinary differential equations. Nonlinear Anal. 40 (2000), No. 1-8, 309-321.

  105. On periodic solutions of systems of differential equations with deviating arguments (with B. Pů杪). Nonlinear Anal. 42 (2000), No. 2, 229-242.

  106. Upper and lower solutions of boundary value problems for functional differential equations and theorems on functional differential inequalities (with R. Hakl and B. Pů杪). Georgian Math. J. 7 (2000), No. 3, 489-512.

  107. On Kneser solutions of the Emden-Fowler differential equation with a negative exponent. Tr. In-ta matematiki NAN Belarusi 4 (2000), 69-77.

  108. On conditions for the existence and uniqueness of periodic solutions of nonautonomous differrential equations (with T. Kusano). (Russian) Differentsial地ye Uravneniya 36 (2000), No. 10, 1301-1306; English transl.: Differ. Equations 36 (2000), No. 10, 1436-1442.

  109. On blow-up Kneser solutions of higher order nonlinear differential equations. (Russian) Differentsial地ye Uravneniya 37 (2001), No. 6, 735-743; English transl.: Differ. Equations 37 (2001), No. 6, 768-777.

  110. On periodic solutions of even-order ordinary differential equations (with T. Kusano). Ann. Mat. Pura Appl. (4) 180 (2001), No. 3, 285-301.

  111. On advanced functional differential equations with properties A and B (with N. Partsvania and I. P. Stavroulakis). Mem. Differential Equations Math. Phys. 24 (2001), 146-150.

  112. On singular boundary value problems for functional differential equations of higher order (with B. Pů杪 and I. P. Stavroulakis). Georgian Math. J. 8 (2001), No. 4, 791-814.

  113. On periodic boundary value problem for the equation  with one-sided growth restrictions on f (with S. Staněk). Nonlinear Anal. 48 (2002), No. 7, 1065-1075.

  114. On the Kneser problem for two-dimensional differential systems with advanced arguments (with N. Partsvania). J. Inequal. Appl. 7 (2002), No. 4, 453-477.

  115. On oscillatory properties of higher order advanced functional differential equations (with N. Partsvania and I. P. Stavroulakis). (Russian) Differentsial地ye Uravneniya 38 (2002), No. 8, 1030-1041; English transl.: Differ. Equations 38 (2002), No. 8, 1095-1107.

  116. Conti-Opial type existence and uniqueness theorems for nonlinear singular boundary value problems (with B. Pů杪). Funct. Differ. Equ. 9 (2002), No. 3-4, 405-422.

  117. On oscillatory solutions of nonlinear differential equations with advanced arguments (with N. Partsvania and I. P. Stavroulakis). Mem. Differential Equations Math. Phys. 25 (2002), 156-158.

  118. On boundary value problems for linear differential systems with singularities. (Russian) Differentsial地ye Uravneniya 39 (2003), No. 2, 198-209.

  119. Some optimal conditions for the solvability of two-point singular boundary value problems. Funct. Differ. Equ. 10 (2003), No. 1-2, 259-281.

  120. On nonlinear boundary value problems for two-dimensional differential systems (with  S. Mukhigulashvili). (Russian) Differentsial地ye Uravneniya 40 (2004), No. 6, 747-755; English transl.: Differ. Equations 40 (2004), No. 6, 797-806.

  121. On some nonlocal boundary value problems for two-dimensional linear differential systems. (Russian) Differentsial地ye Uravneniya (accepted).

  122. On periodic type solutions of systems of linear ordinary differential equations. Abstr. Appl. Anal. 2004, No. 5, 395-406.

  123. On two-point boundary value problems for higher order singular ordinary differential equations. Mem. Differential Equations Math. Phys. 32 (2004), 101-107.

  124. On the solvability of nonlinear operator equations in a Banach space. Mem. Differential Equations Math. Phys. 32 (2004), 127-130.

  125. On periodic solutions of two-dimensional nonautonomous differential systems (with S. Mukhigulashvili). Nonlinear Anal. Appl. (accepted).