1. E. Grigat and R. Putter, Angew Chem. Internat. Edit 6, 206 (1967).
2. D. Martin, Angew Chem. Internat. Edit 3, 311 (1964).
3. K. A. Jenson and A. Holm, Acta Chem. Scand. 18, 826 (1964).
4. K. K. Weirauch, P.G. Gemeinhardt, a. L. Baron, Soc. Plast. Eng., Tech Paper 22, 317–21 (1976).
5. J. L. Cercena, S. J. Huang, Polymer Preprint (ACS Div. Polm. Chem.), 25 (1), 114.