@article{IM2_1998_62_6_a1,
     author = {A. G. Babenko},
     title = {An exact {Jackson--Stechkin} inequality for $L^2$-approximation on the interval with the {Jacobi} weight and on projective spaces},
     journal = {Izvestiya. Mathematics },
     pages = {1095--1119},
     publisher = {mathdoc},
     volume = {62},
     number = {6},
     year = {1998},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1998_62_6_a1/}
}