MR1662369 Burton, T. A. and Furumochi, Tetsuo T. A. BURTON and Tetsuo FURUMOCHI Funkcialaj Ekvacioj. Serio Internacia 41 1998 327--336 http://fe.math.kobe-u.ac.jp/FE/FullPapers/vol41/fe41-2-11.pdf http://fe.math.kobe-u.ac.jp/FE/FE_pdf_with_bookmark/FE41-45-en_KML/fe41-327-336/fe41-327-336.pdf http://www.ams.org/mathscinet-getitem?mr=MR1662369 fe41-327-336 1998 BURTON, T. A.; FURUMOCHI, Tetsuo BURTON, T. A.; FURUMOCHI, Tetsuo 1 Coddington, E. A.; Levinson, N. Theory of Ordinary Differential Equations McGraw-Hill, New York 1955 MR0069338 100 Cache/Co/Coddington,Ordinary,*,1955,1956 xii+429 2 Hale, J. K. Theory of Functional Differential Equations Springer, New York 1977 MR0508721 100 Cache/Ha/Hale,Functional,*,1977,1978 x+365 3 Lakshmikantham, V.; Zhang, B.; Wen, L. Theory of Differential Equations with Unbounded Delay Kluwer, Dorbrecht 1994 MR1319339 100 Cache/La/Lakshmikantham,Theory,*,1994,1995 xii+385 4 Smart, D. R. Fixed Point Theorems Cambridge Univ. Press, Cambridge 1980 MR0467717 Cache/Sm/Smart,Theorems,*,1980,1981