Inter-clinic variation in the chances of natural conception of subfertile couples

R. I. Tjon-Kon-Fat, D. N. Lar, E. W. Steyerberg, F. J. Broekmans, P. Hompes, B. W.J. Mol, P. Steures, P. M.M. Bossuyt, F. Van Der Veen, J. W. Van Der Steeg, M. J.C. Eijkemans^*

^*Corresponding author for this work