@article{TRSPY_2015_288_a14, author = {Imre B\'ar\'any and Ruy Fabila-Monroy and Birgit Vogtenhuber}, title = {$(n,m)$-fold covers of spheres}, journal = {Informatics and Automation}, pages = {224--229}, publisher = {mathdoc}, volume = {288}, year = {2015}, language = {en}, url = {http://geodesic.mathdoc.fr/item/TRSPY_2015_288_a14/} }