@article{SM_1977_32_4_a5,
     author = {S. S. Marchenkov},
     title = {On recursively enumerable minimal btt-degrees},
     journal = {Sbornik. Mathematics},
     pages = {477--487},
     publisher = {mathdoc},
     volume = {32},
     number = {4},
     year = {1977},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1977_32_4_a5/}
}