@article{SM_2012_203_8_a6,
     author = {F. N. Pakhomov},
     title = {Undecidability of the elementary theory of the semilattice of {GLP-words}},
     journal = {Sbornik. Mathematics},
     pages = {1211--1229},
     year = {2012},
     volume = {203},
     number = {8},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2012_203_8_a6/}
}