Susan S Jick, Rohini K Hernandez
Jick S S, Hernandez R K.
Risk of non-fatal venous thromboembolism in women using oral contraceptives containing drospirenone compared with women using oral contraceptives containing levonorgestrel: case-control study using United States claims data
BMJ 2011; 342 :d2151
doi:10.1136/bmj.d2151