[1] LAPIN UNIHAMMAS INC,ROVANIEMI,FINLAND
[2] UNIV HELSINKI,CENT HOSP,DEPT ANAESTHESIA,SF-00170 HELSINKI 17,FINLAND
[3] UNIV HELSINKI,CENT HOSP,DEPT OBSTET & GYNAECOL 1,SF-00170 HELSINKI 17,FINLAND
[4] UNIV HELSINKI,CENT HOSP,DEPT OBSTET & GYNAECOL 2,SF-00170 HELSINKI 17,FINLAND