Crossover designs versus parallel studies in infertility research.
te Velde
E R
ER
Cohlen
B J
BJ
Looman
C W
CW
Habbema
J D
JD
D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000628:therapy*; D012107:Research Design