1. 2) Laivins G. V. and Scallan A. M. : Transactions of the 10 th Fundamental Research Symposium held at Oxford Pira, UK, 1993, p. 1235
2. 4) Howard R. C. : J. Pulp Pap Sci. 16 (5) J 143 (1990)
3. 5) Weston J. D. W. and Guest D. A. : Paper Techn. Ind., 26, 309 (1985)