TY  - BOOK
AU  - Fritsch, Rudolf
AU  - Fritsch, Gerda
AU  - Peschke, Julie
TI  - The Four-color theorem: History, topological foundations and idea of proof 
SN  - 9780387984971
U1  - 511.5 20
PY  - 1998///
CY  - New York
PB  - Springer-Verlag
KW  - Mathematics
KW  - Four-color problem
ER  -