ANDRICA, Dorin, et al. 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, 2007, https://editura.ubbcluj.ro/index.php/puc/catalog/book/3725.