@article{MZM_1969_5_3_a6,
     author = {B. S. Pitskel'},
     title = {Some properties of $A$-entropy},
     journal = {Matemati\v{c}eskie zametki},
     pages = {327--334},
     publisher = {mathdoc},
     volume = {5},
     number = {3},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1969_5_3_a6/}
}