PUVA and cancer: a large-scale epidemiological study. - Lindelöf,B.; Sigurgeirsson,B.; Tegner,E.; Larkö,O.; Johannesson,A.; Berne,B.; Christensen,O.B.; Andersson,T.; Törngren,M.; Molin,L.; Nylander-Lundqvist,E.; Emtestam,L. (Lancet, 1991)