@article{AUCMP_2012_53_2_a5,
     author = {Gagola, Stephen  III, and Kepka, Tom\'a\v{s}},
     title = {Transitive closures of binary relations. {IV}},
     journal = {Acta Universitatis Carolinae. Mathematica et Physica},
     pages = {47--60},
     year = {2012},
     volume = {53},
     number = {2},
     mrnumber = {3099640},
     zbl = {06186449},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUCMP_2012_53_2_a5/}
}