TY  - JOUR
AU  - Behzad, Mehdi
AU  - Harary, Frank
TI  - Which directed graphs have a solution?
JO  - Mathematica slovaca
PY  - 1977
SP  - 37
EP  - 42
VL  - 27
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MASLO_1977__27_1_a4/
LA  - en
ID  - MASLO_1977__27_1_a4
ER  -