@article{CM_1968__20__211_0,
     author = {Troelstra, A. S.},
     title = {New sets of postulates for intuitionistic topology},
     journal = {Compositio Mathematica},
     pages = {211--221},
     publisher = {Wolters-Noordhoff Publishing},
     volume = {20},
     year = {1968},
     mrnumber = {235985},
     zbl = {0164.30804},
     language = {en},
     url = {http://www.numdam.org/item/CM_1968__20__211_0/}
}