[1] Burton T A. Periodic solutions of linear Volterra equations. Funkcial Ekvac, 1984, 27:229-253

[2] Langenhop C E. Periodic and almost periodic solutions of Volterra integral differential equations with
infinite memory. J Diff Eqns, 1985, 58:391-403

[3] Murakami S. Periodic solutions of some integro-differential equations. Res Rep Hachinohe National College
21(Dec.1986),131-133

[4] Murakami S. Linear periodic functional differential equations with infinite delay. Funkcial Ekvac, 1986,
29:335-361

[5] Hatvani L, Krisztin T. On the existence of periodic solutions for linear inhomogeneous and quasilinear
functional differential equations. J Diff Eqns, 1992, 97:1-15

[6] Wang Z C. Periodic solutions of linear neutral integrodifferential equations. Tˆohoku Math J, 1986,38:71-83

[7] Wang Z C. Periodic solutions of linear nonconvolute Volterra integral equations and integrodifferential
equations. Acta Math Appl Sinica, 1991, 14(2):145-154

[8] Zhang Y, Zhang Y. On the periodic solutions of linear neutral equations of second order with constant
coefficients. Acta Math Sinica, 1991, 33(4):517-520

[9] Rong H W, Xu W, Zhang D C. Periodic solutions of linear autonomous neutral differential equations with
delay(To appear)

[10] Zhang M R. Periodic solutions of linear and quasilinear neutral functional differential equations. J Math
Anal Appl, 1995, 189:378-392

[11] Ma S W, Yu J S,Wang Z C. Periodic solutions of periodically perturbed functional differential equations.
Chinese Science Bulletin, 1998, 43:1956-1959

[12] Ma S W, Wang Z C, Yu J S. Periodic solutions of functional differential equations with a quasibonded
perturbation. Funkcial Ekvac, 2001, 44

[13] Ma S W, Wang Z C, Yu J S. The existence and uniqueness of periodic solutions of quasilinear functional
differencial equations. Chinese Ann Math, 2001, 22A: 105-110