@article{GDZPPN002481650,
title = {Best Coapproximation in Normed Linear Spaces.},
journal = {Monatshefte f\"ur Mathematik},
volume = {87},
year = {1979},
pages = {27-44},
zbl = {0421.41017},
url = {http://dml.mathdoc.fr/item/GDZPPN002481650}
}
Singer, Ivan; Papini, Pier L. Best Coapproximation in Normed Linear Spaces.. Monatshefte für Mathematik, Tome 87 (1979) pp. 27-44. http://gdmltest.u-ga.fr/item/GDZPPN002481650/