1. Hornby, A.S. and Wehmeier, S. (1995) Oxford Advanced Learner’s Dictionary (Vol. 1428). Oxford University Press, Oxford.
2. HIV/AIDS, Joint United Nations Program on HIV/AIDS (2011) UNAIDS World AIDS Day Report 2011, UNAIDS, Geneva, Switzerland.
3. HIV/AIDS, Joint United Nations Program On HIV/AIDs (2012) UNAIDS Report on the Global AIDS Epidemic. UNAIDS, Geneva, Switzerland.
4. Factors associated with adolescent pregnancies among secondary school students. a study from Tanga-Tanzania.
5. Age-disparate relationships and HIV incidence in adolescent girls and young women