1. Stephen, W. E., Chimia, 1965, 19, 261 UK 797,946 and 798,121 (ICI).
2. Preston, C. and A. S. Fern, Chimia, 1961, 15, 177.
3. Fierz-David, H. E. and M. Matter, J.S.D.C., 1937, 53, 424
4. E. M. Smoun and L. Rapoport, The Chemistry of Heterocyclic Compounds: s-Triazines and Derivatives, 1959, Interscience, New York.
5. Calin, C., V. Sandulescu, S. Rosenberg and E. Tibrea, Coloristica
(Buletin Informativ al Laboratorului Central Coloristic), 1968, 4, (No. 11), 179.