@article{CMUC_1988_29_3_a10,
     author = {Sochor, Anton{\'\i}n},
     title = {Addition of initial segments. {I}},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {501--517},
     year = {1988},
     volume = {29},
     number = {3},
     mrnumber = {972833},
     zbl = {0658.03030},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1988_29_3_a10/}
}