TY  - BOOK
AU  - Harary Frank, and others
TI  - Structural models :  An introduction to the theory of directed graphs   
U1  - B6, K5 
PY  - 1965///
CY  - New York
PB  - Wiley         
KW  - Geometry
N1  - Bibliography: P 392-395; Glossary: P 404-410
ER  -