1. Developments in polymer stabilisation—2;Ayrey,1980
2. Developments in polymer stabilisation—2;Cooray,1980
3. Stabilisation and degradation of polymers;Starnes;Adv. in Chem. Series,1978
4. J. W. Burley, R. E. Hutton and B. R. Iles, Ger. Pat. 2,540,210 (25th March, 1976).