@article{ZNSL_1976_60_a12,
     author = {S. V. Pakhomov},
     title = {Hierarchies of operators in constructive metric spaces},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {183--193},
     publisher = {mathdoc},
     volume = {60},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1976_60_a12/}
}