The influence of intracervical and intravaginal application of seminal plasma on the endometrium and life birth rate: a prospective, double-blind, placebo-controlled, randomized study - Mayer Richard, B; Shebl, O; Krain, V; Hartl, J; Oppelt, P; Ebner, T (Geburtshilfe und Frauenheilkunde, 2013)