R. Bellman and K.L. Cooke, Differential-Difference Equations, Acadmic Press, New York-London, 1963.
Google Scholar
T.A. Burton, Stability by Fixed Point Theory for Functional Differential Equations, Dover Publications, Inc., Mineola, NY, 2006.
Google Scholar
S.N. Chow, Existence of periodic solutions of autonomous functional differential equations, J. Differential Equations 15 (1974), 350–378.
Google Scholar
K.L. Cooke, Functional differential equations: some models and perturbation problems, in: J.K. Hale and J.P. LaSalle (eds.), Differential Equations and Dynamical Systems (Proc. Internat. Sympos., Mayaguez, P.R., 1965), Academic Press, New York-London, 1967, pp. 167–183.
Google Scholar
E. Eder, The functional differential equation x'(t) = x(x(t)), J. Differential Equations 54 (1984), 390–400.
Google Scholar
M. Fečkan, On a certain type of functional-differential equations, Math. Slovaca 43 (1993), 39–43.
Google Scholar
J. Hale, Theory of Functional Differential Equations, Springer-Verlag, New York-Heidelberg, 1977.
Google Scholar
J. Liu and J.G. Si, Analytic solutions for a class of differential equation with delays depending on state, Appl. Math. Comput. 186 (2007), 261–270.
Google Scholar
B.T. Polyak, Existence theorems and convergence of minimizing sequences in extremum problems with restrictions, Soviet Math. Dokl. 7 (1966), 72–75.
Google Scholar
Y.N. Raffoul, Positive periodic solutions in neutral nonlinear differential equations, Electron. J. Qual. Theory Differ. Equ. 2007, No. 16, 10 pp.
Google Scholar
A.W. Roberts and D.E. Varberg, Convex Functions, Academic Press, New York-London, 1973.
Google Scholar
J.G. Si and S.S. Cheng, Smooth solutions of a nonhomogeneous iterative functionaldifferential equation, Proc. Roy. Soc. Edinburgh Sect. A 128 (1998), 821–831.
Google Scholar
J.G. Si, W.R. Li, and S.S. Cheng, Analytic solutions of an iterative functionaldifferential equation, Comput. Math. Appl. 33 (1997), 47–51.
Google Scholar
J.G. Si and X.P. Wang, Smooth solutions of a nonhomogeneous iterative functionaldifferential equation with variable coefficients, J. Math. Anal. Appl. 226 (1998), 377–392.
Google Scholar
D.R. Smart, Fixed Point Theorems, Cambridge University Press, Cambridge, 1980.
Google Scholar
S. Staněk, On global properties of solutions of functional-differential equation x'(t) = x(x(t)) + x(t), Dynam. Systems Appl. 4 (1995), 263–278.
Google Scholar
K. Wang, On the equation x'(t) = f(x(x(t))), Funkcial. Ekvac. 33 (1990), 405–425.
Google Scholar
X.P. Wang and J.G. Si, Analytic solutions of an iterative functional differential equation, J. Math. Anal. Appl. 262 (2001), 490–498.
Google Scholar
B. Xu and W.N. Zhang, Decreasing solutions and convex solutions of the polynomial-like iterative equation, J. Math. Anal. Appl. 329 (2007) 483–497.
Google Scholar
W.N. Zhang, K. Nikodem, and B. Xu, Convex sulutions of polynomial-like iterative equations, J. Math. Anal. Appl. 315 (2006) 29–40.
Google Scholar
H.Y. Zhao and J. Liu, Periodic solutions of an iterative functional differential equation with variable coefficients, Math. Methods Appl. Sci. 40 (2017), 286–292.
Google Scholar