@article{AL_1979_18_6_a2,
     author = {A. N. Degtev},
     title = {Some results on upper semilattices and $m$-degrees},
     journal = {Algebra i logika},
     pages = {664--679},
     publisher = {mathdoc},
     volume = {18},
     number = {6},
     year = {1979},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1979_18_6_a2/}
}