TY - JOUR TI - CJM volume 71 Issue 4 Cover and Back matter JO - Canadian journal of mathematics PY - 2019 SP - b1 EP - b2 VL - 71 IS - 4 UR - http://geodesic.mathdoc.fr/articles/10.4153/S0008414X19000361/ DO - 10.4153/S0008414X19000361 ID - 10_4153_S0008414X19000361 ER -