@article{PIM_1991_N_S_50_64_a2,
     author = {\v{Z}arko Mijajlovi\'c},
     title = {Definable {Ultrapowers} and the {Omitting} {Types} {Theorem}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {14 },
     year = {1991},
     volume = {_N_S_50},
     number = {64},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PIM_1991_N_S_50_64_a2/}
}