1. Erk P, Hengelsberg H (2003) In: Kadish K, Guilard R, Smith KM (eds) The porphyrin handbook. Academic Press, New York
2. Radtke V, Erk P, Sens B (2002) In: Smith H (ed) High performance pigments. Wiley-VCH, Weinheim
3. Vollmann H (1971) In: Venkataraman K (ed) The chemistry of synthetic dyes. Academic Press, New York
4. Rösch G, Wolf W, Vollmann H (1954) Chem Abstr 48:30802
5. Elvidge JA, Barot NR (1977) In: Patai S (ed) The chemistry of double-bonded functional groups. Wiley, London