1. Wolbach SB, Todd JL, Palfrey FW:The Etiology of Pathology Thymus. Harvard University Press, Cambridge, MA, 1922, pp 13–14
2. Luna LG:Manual of Histologic Staining Methods of the Armed Forces Institute of Pathology, 3rd ed. McGraw-Hill, New York, 1969, pp 121–122, 235–237