@article{AL_2021_60_1_a0,
     author = {M. I. Bekenov and A. M. Nurakunov},
     title = {A semigroup of theories and its lattice of idempotent elements},
     journal = {Algebra i logika},
     pages = {3--22},
     publisher = {mathdoc},
     volume = {60},
     number = {1},
     year = {2021},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_2021_60_1_a0/}
}