A Prospective Study of Chlamydia pneumoniae Antibodies in Children Between 7 months and 8 years of Age. - Volanen, Iina; Vainionpää, Raija; Ilonen, Jorma; Markula, Perttu; Kallio, Katariina; Kaitosaari, Tuuli; Helenius, Hans; Simell, Olli (Scandinavian Journal of Infectious Diseases, 2003)