1. World wide prevalence of anaemia 1993-2005 WHO Global Database on Anaemia. Available from: http://www.whqlibdoc.who.int/publications/./9789241596657_eng.pdf. [Last accessed on 30 Jul 2012].
2. World Health Organization. Manual of basic techniques for a health laboratory. 1980. p. 271-8
3. World Health Organization. Nutritional anemia: Report of a WHO Scientific Group. Geneva, Switzerland: World Health Organization; 1968.