1. Displacement
2. Lillie RD: H.I. Conn's Biological Stains, 8th Edition. Williams and Wilkins Co., Baltimore, 1960, p. 238.
3. Lillie RD and Fullmer HM:Histopathologic Technic and Practical Histochemistry, 4th Edition. McGraw-Hill Book Co., N.Y., 1976, pp. 31–34.
4. Hard and soft acids and bases, HSAB, part 1: Fundamental principles