TY - JOUR DP - http://iris.who.int/ DB - WHO IRIS EP - 260 AU - World Health Organization LA - en LA - fr UR - https://iris.who.int/handle/10665/221470 JF - Weekly Epidemiological Record = Relevé épidémiologique hebdomadaire DA - 1977 PY - 1977 IS - 31 SP - 253 TI - Weekly Epidemiological Record, 1977, vol. 52, 31 [full issue] VL - 52 ER -