1. R. C. Bertelson, in: Photochromism, G. H. Brown (ed.), Wiley, New York (1971), pp. 49?294.
2. V. A. Barachevskii, G. I. Lashkov, and V. A. Tsekhomskii, Photochromism and its Application [in Russian], Khimiya, Moscow (1977).
3. A. V. El'tsov (ed.), Photochromism [in Russian], Khimiya, Leningrad (1982).
4. H. Durr and H. Bouas-Laurent (eds.), Photochromism, Elsevier, Amsterdam (1990).
5. H. Durr, Angew. Chem., 101, No. 3, 427 (1989).