Association between Chlamydia trachomatis antibodies and subfertility in the Northern Finland Birth Cohort 1966 (NFBC 1966), at the age of 31 years - Karinen L; Pouta A; Hartikainen A-L; Bloigu A; Paldanius M; Leinonen M; Saikku P; Järvelin M-R (2004)