@article{MZM_1987_41_6_a4,
     author = {F. V. Guseinov},
     title = {Jensen's inequality},
     journal = {Matemati\v{c}eskie zametki},
     pages = {798--806},
     publisher = {mathdoc},
     volume = {41},
     number = {6},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1987_41_6_a4/}
}