1. Boelskifte J, Saval PM, Rasmussen KL (2002) Sexual activity and contraception habits among adolescents over the last 14 years. An investigation among 9th grade pupils in the municipality of Viborg. In Danish Ugeskr f Laeger 164:3207–3211
2. Wielandt HB, Jeune B (1992) Did debut of intercourse change after the safe-sex campaign? In Danish Ugeskr Laeger 154:271–275
3. Larsen SB, Kragstrup J (1997) Age at menarche and first intercourse. In Danish Ugeskr Laeger 159:6676–6679
4. Magnusson C (2001) Adolescent girls’ sexual attitudes and opposite-sex relations in 1970 and in 1996. J Adolesc Health 28:242–252
5. National Board of Health’s homepage on Deliveries, Fertility treatment and abortion: Contraception and abortions 1993, congenital malformations 1992 and 1993. Informatics and health data. Publications on Health Statistics at: http://www.sst.dk/Informatik_og_sundhedsdata.aspx?lang=en