1. A.R. Katritzky (Ed.), Pyrylium Salts: Syntheses, Reactions and Physical Properties, Advances in Hetreocyclic Chemistry, Supplementary 2, Academic Press, New York, 1982.
2. G. Dorofeenko, E. Sadekova, E. Kuznezov, Preparativnaja Khimia Pyrylievich Soleyi, Izd.Rostov. Univ., Rostov-na Donu, 1972 (in Russian).
3. New laser dyes
4. Corrélation entre possibilité d'effet laser et force oscillatrice de la transition fluorescente : cas des sels de pyrylium
5. Pol. Pat. 151 04; Chemical Abstracts 115, 258291s (1990).