@article{IVM_1998_2_a3,
     author = {A. A. Efremov},
     title = {$d$-r.e.\ degrees that are isolated from {above.~I}},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {20--28},
     publisher = {mathdoc},
     number = {2},
     year = {1998},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1998_2_a3/}
}