1. Mees, K., James, T.H.: The Theory of the Photographic Process. New York: McMillan 1966
2. Pryor, W.A.: Free Radicals. New York: McGraw-Hill 1960
3. Ayscough, P.B.: Electron Spin Resonance in Chemistry. London: Methuen 1967
4. Venkataraman, B., Fraenkel, G.K.: J. Amer. Chem. Soc.77, 2707 (1955)
5. Ashworth, P., Dixon, W.T.: Chem. Commun.1971, 1150