TY  - BOOK
AU  - Eberlein, Patrick
TI  - Surfaces of Nonpositive Curvature
T2  - Memoirs of the American Mathematical Society, vol 20, No.218
SN  - 0821822187
U1  - 516.362 
PY  - 1979///
CY  - Providence
PB  - American Mathematical Society
ER  -