@article{IIGUM_2022_40_a7,
     author = {Nurlan D. Markhabatov},
     title = {Approximations of acyclic graphs},
     journal = {The Bulletin of Irkutsk State University. Series Mathematics},
     pages = {104--111},
     year = {2022},
     volume = {40},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IIGUM_2022_40_a7/}
}