@article{MT_1989_14_a6,
     author = {S. S. Kutateladze},
     title = {Directions in nonstandard analysis},
     journal = {Matemati\v{c}eskie trudy},
     pages = {153--182},
     publisher = {mathdoc},
     volume = {14},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MT_1989_14_a6/}
}