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2. Evatt BL, Gibbs WN, Lewis SM, McArther JR.Fundamental Diagnostic Hematology: The Bleeding and Clotting Disorders. 2nd ed. Geneva, Switzerland: WHO Publications; 1992:79–83.
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4. Lewis SM, Verwilgen RL.Quality Assurance in Haematology. London: Bailleere Tindall; 1988:5–26.
5. Standardization of blood specimen collection procedure for reference values. International Committee for Standardization in Haematology (ICSH).Clin Lab Haematol. 1982;4:83–86.