@article{10_4064_fm_53_1_43_49,
     author = {J. Isbell},
     title = {Two set-theoretical theorems in categories},
     journal = {Fundamenta Mathematicae},
     pages = {43--49},
     publisher = {mathdoc},
     volume = {53},
     number = {1},
     year = {1964},
     doi = {10.4064/fm-53-1-43-49},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-53-1-43-49/}
}