Chronic Chlamydia pneumoniae infection as a risk factor for coronary heart disease in the Helsinki Heart Study - Saikku, P; Leinonen, M; Tenkanen, L; Linnanmäki, E; Ekman, MR; Manninen, V; Mänttäri, M; Frick, H; Huttunen, JK (Ann Intern Med, 1992)