Preprint. ``Babeş-Bolyai'' University. Faculty of Mathematics. Research Seminars. ``Babeş-Bolyai'' University, Faculty of Mathematics, Cluj-Napoca. English, French.

Journal

Continued as: Prepr., ``Babeş-Bolyai'' Univ., Fac. Math. Phys., Res. Semin.

No longer indexed.