1. (a)Studies in Organic Chemistry; Durr, H., Bouas-Laurant, H., Eds.; Photochromism: Molecules and Systems, 40; Elsevier: Amsterdam, 1990; Chapters 23−29.
2. (b) Scheffer, R. J.; Pokkuluri, P. R. InPhotochemistry inOrganized and Constrained Media; Ramamurthy, V., Ed.; VCH: New York, 1991; p 185.
3. Photochromotropic behaviour of 2-(2?,4?-dinitrobenzyl)-pyridine