@article{DE_1998_34_1_a15,
     author = {A. M. Nakhushev},
     title = {On the positivity of continuous and discrete differentiation and integration operators that are very important in fractional calculus and in the theory of equations of mixed type},
     journal = {Differencialʹnye uravneni\^a},
     pages = {101--109},
     publisher = {mathdoc},
     volume = {34},
     number = {1},
     year = {1998},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1998_34_1_a15/}
}