@article{VMUMM_2006_5_a0,
     author = {V. G. Kanovei and V. A. Uspenskii},
     title = {Uniqueness of nonstandard extensions},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {3--10},
     publisher = {mathdoc},
     number = {5},
     year = {2006},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_2006_5_a0/}
}