@article{CTGDC_1974__15_2_157_0,
     author = {Osius, Gerhard},
     title = {The internal and external aspect of logic and set theory in elementary topoi},
     journal = {Cahiers de topologie et g\'eom\'etrie diff\'erentielle},
     pages = {157--180},
     publisher = {Dunod \'editeur, publi\'e avec le concours du CNRS},
     volume = {15},
     number = {2},
     year = {1974},
     mrnumber = {387049},
     zbl = {0362.18001},
     language = {en},
     url = {http://www.numdam.org/item/CTGDC_1974__15_2_157_0/}
}