1. J. Bernstein , Polymorphism in Molecular Crystals, Oxford University Press, 2008
2. W. C. McCrone , Polymorphism in Physics and Chemistry of the Organic Solid State, ed. D. Fox, M. M Labes and A. Weissberger, Interscience, New York, 1965, vol. II, pp. 728–731
3. Analysis of organic polymorphs. A review
4. Counterpoint: What's in a Name?