MR1078135 Kitamura, Yuichi and Kusano, Taka{\^s}i Yuichi KITAMURA and Takaŝi KUSANO Funkcialaj Ekvacioj. Serio Internacia 33 1990 325--343 http://fe.math.kobe-u.ac.jp/FE/Free/vol33/fe33-2-9.pdf http://fe.math.kobe-u.ac.jp/FE/FE_pdf_with_bookmark/FE31-34-en_KML/fe33-325-343/fe33-325-343.pdf http://www.ams.org/mathscinet-getitem?mr=MR1078135 fe33-325-343 1990 KITAMURA, Yuichi; KUSANO, Takasi KITAMURA, Yuichi; KUSANO, Takasi 1 Ivanov, A. F.; Kusano, T., Oscillation of solutions of a class of first order functional differential equations of neutral type, to appear in Ukrain. Mat. Ž. (Russian) MR1034680