TY  - JOUR
AU  - Graham, R. L.
TI  - On Subtrees of Directed Graphs with No Path of Length Exceeding One
JO  - Canadian mathematical bulletin
PY  - 1970
SP  - 329
EP  - 332
VL  - 13
IS  - 3
UR  - http://geodesic.mathdoc.fr/articles/10.4153/CMB-1970-063-1/
DO  - 10.4153/CMB-1970-063-1
ID  - 10_4153_CMB_1970_063_1
ER  -