@article{PIM_1980_N_S_28_42_a5,
     author = {Dipak Chatterjee},
     title = {M-convexity and {Best} {Approximation}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {43 },
     publisher = {mathdoc},
     volume = {_N_S_28},
     number = {42},
     year = {1980},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PIM_1980_N_S_28_42_a5/}
}