@article{ARM_1968_4_1_a1,
     author = {Sekanina, Milan},
     title = {Categories of ordered sets},
     journal = {Archivum mathematicum},
     pages = {25--59},
     year = {1968},
     volume = {4},
     number = {1},
     mrnumber = {0263721},
     zbl = {0196.03701},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ARM_1968_4_1_a1/}
}