TY  - JOUR
AU  - Marica, J.
AU  - Schöheim, J.
TI  - Differences of Sets and A Problem of Graham
JO  - Canadian mathematical bulletin
PY  - 1969
SP  - 635
EP  - 637
VL  - 12
IS  - 5
UR  - http://geodesic.mathdoc.fr/articles/10.4153/CMB-1969-081-4/
DO  - 10.4153/CMB-1969-081-4
ID  - 10_4153_CMB_1969_081_4
ER  -