TY - JOUR TI - Problems for Solution JO - Canadian mathematical bulletin PY - 1964 SP - 473 EP - 478 VL - 7 IS - 3 UR - http://geodesic.mathdoc.fr/articles/10.1017/S000843950003188X/ DO - 10.1017/S000843950003188X ID - 10_1017_S000843950003188X ER -