Voir la notice de l'article provenant de la source Mathematicac Balkanica website
@article{MABA_2002_16_1-4_a2, author = {M.D. Takev}, title = {Direct and {Inverse} {Approximation} {Theorems} in {R2}}, journal = {Mathematica balkanica}, pages = {53}, publisher = {mathdoc}, volume = {16}, number = {1-4}, year = {2002}, url = {http://geodesic.mathdoc.fr/item/MABA_2002_16_1-4_a2/} }
M.D. Takev. Direct and Inverse Approximation Theorems in R2. Mathematica balkanica, Tome 16 (2002) no. 1-4, p. 53. http://geodesic.mathdoc.fr/item/MABA_2002_16_1-4_a2/