De Blasi, F S.(2004). Approximate selections in ${\alpha}$-convex metric spaces and topological degree. Topological Methods in Nonlinear Analysis, 24(2), 347. doi:10.12775/tmna.2004.032

De Blasi, Francesco S. "Approximate Selections in ${\alpha}$-convex Metric Spaces and Topological Degree". Topological Methods in Nonlinear Analysis, 24.2 ( 2004 ): 347.