@article{VMP_2000_1_2_a4,
     author = {A. D. Kovalev and V. V. Nikitin},
     title = {Sets in the tool environment for developing program modules},
     journal = {Numerical methods and programming},
     pages = {31--36},
     publisher = {mathdoc},
     volume = {1},
     number = {2},
     year = {2000},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMP_2000_1_2_a4/}
}