@article{PIM_2001_N_S_69_83_a3,
     author = {Milan Grulovi\'c},
     title = {Comments on {Ultraproducts} of {Forcing} {Systems}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {18 },
     publisher = {mathdoc},
     volume = {_N_S_69},
     number = {83},
     year = {2001},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PIM_2001_N_S_69_83_a3/}
}