1. G. Kapo, in: G.V. Chilingarian, T.F. Yen (Eds.), Bitumens, Asphalts and Tar Sands, chapter 8, Elsevier, Amsterdam, 1978
2. T.F. Yen, in: T.F. Yen (Ed.), The Role of Trace Metal in Petroleum, chapter I, II, Ann Arbor Science Publishers, Ann Arbor, MI, 1975
3. E.W. Baker, S. Palmer, in: D. Dolphin (Ed.), The Porphyrins, vol. II, chapter 8, Academic Press, New York, 1978