TY  - JOUR
AU  - Schirmer, Helga
TI  - Coincidence Producing Maps Onto Trees
JO  - Canadian mathematical bulletin
PY  - 1967
SP  - 417
EP  - 423
VL  - 10
IS  - 3
UR  - http://geodesic.mathdoc.fr/articles/10.4153/CMB-1967-039-x/
DO  - 10.4153/CMB-1967-039-x
ID  - 10_4153_CMB_1967_039_x
ER  -