TY - JOUR AU - Eriksson, A W; Fellman, J TI - Seasonal variation of livebirths, stillbirths, extramarital births and twin maternities in Switzerland JO - Twin Res IS - 04 VL - 3 PY - 2000 DO - 10.1375/136905200320565148 L3 - PubMed-ID: 11463138 SP - 189 EP - 201 ER -