For a more detailed discussion, see Josef T. Prchal and Perumal Thiagaragan: Erythropoiesis, Chap. 32; Archana M. Agarwal and Josef T. Prchal: Methemoglobinemia and other dyshemoglobinemias, Chap. 50; Josef T. Prchal: Primary and Secondary Polycythemias (Erythrocytosis), Chap. 57 in Williams Hematology, 9th ed.