Show all abstractsHide all abstracts

C. R. Math. Rep. Acad. Sci. Canada Vol. 17 (1) 1995, pp. 1–6
H. Ben-El-Mechaiekh / P. Deguire (Received: 1994/08/09, Revised: 1994/11/11) C. R. Math. Rep. Acad. Sci. Canada Vol. 15 (6) 1993, pp. 243–248
X.-Z. Yuan (Received: 1993/07/21)