00390nas a2200121   4500000000100000000000100001008004100002100001200043245016400055300000900219490000800228022003200236       2000                            d1 aH. Jick00aIncidence of venous thromboembolism in users of combined oral contraceptives. Methods for identifying cases and estimating person time at risk must be detailed  a57-80 v320  a0959-8138 (Print) 0959-8138