ANDRICA, D., BLAGA, P., & MOROIANU, S. (2007). MODERN TRENDS IN GEOMETRY AND TOPOLOGY: THE 7TH INTERNATIONAL WORKSHOOP ON DIFFERENTIAL GEMETRY AND ITS APPLICA-TIONS : DEVA, SEPTEMBER 5TH- SEPTEMBER 11TH, 2005. Presa Universitară Clujeană. https://editura.ubbcluj.ro/index.php/puc/catalog/book/3725