@article{SEMR_2014_11_a13,
     author = {S. P. Odintsov and V. V. Rybakov},
     title = {Unification {Problem}  in {Nelson's} {Logic} $\mathbf{N4}$},
     journal = {Sibirskie \`elektronnye matemati\v{c}eskie izvesti\^a},
     pages = {434--443},
     publisher = {mathdoc},
     volume = {11},
     year = {2014},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SEMR_2014_11_a13/}
}