@article{TRSPY_2006_252_a21, author = {M. I. Shtogrin}, title = {Positivity of {Curvature} and {Convexity} of {Faces}}, journal = {Informatics and Automation}, pages = {277--284}, publisher = {mathdoc}, volume = {252}, year = {2006}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/TRSPY_2006_252_a21/} }