TY  - BOOK
AU  - Gaines, Robert E
AU  - Mawhin, Jean L
TI  - Concidence degree, and nonlinear differential equations
T2  - Lecture Notes in Mathematics, No.0568
U1  - R  LNM.0568 
PY  - 1977///
CY  - Springer-Verlag, Berlin
KW  - Lecture Notes in Mathematics
ER  -