@article{PORMA_1960__19_2_114835,
     author = {Morgado, Jos\'e},
     title = {Some results on closure operators of partially ordered sets},
     journal = {Portugaliae mathematica},
     pages = {101--139},
     year = {1960},
     volume = {19},
     number = {2},
     mrnumber = {0133260},
     zbl = {0103.26702},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1960__19_2_114835/}
}