@article{CTGDC_2010__51_3_224_0,
     author = {Kock, Anders},
     title = {Abstract projective lines},
     journal = {Cahiers de Topologie et G\'eom\'etrie Diff\'erentielle Cat\'egoriques},
     eid = {4},
     pages = {224--240},
     publisher = {Andr\'ee CHARLES EHRESMANN},
     volume = {51},
     number = {3},
     year = {2010},
     mrnumber = {2731719},
     zbl = {1223.51001},
     language = {en},
     url = {http://www.numdam.org/item/CTGDC_2010__51_3_224_0/}
}