@article{10_4153_CMB_1975_008_x,
     author = {Jorgensen, Murray},
     title = {Regular {Ultrafilters} and {Long} {Ultrapowers}},
     journal = {Canadian mathematical bulletin},
     pages = {41--43},
     year = {1975},
     volume = {18},
     number = {1},
     doi = {10.4153/CMB-1975-008-x},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1975-008-x/}
}