@article{CM_1968__20__21_0,
     author = {Van Dalen, Dirk},
     title = {A note on spread-cardinals},
     journal = {Compositio Mathematica},
     pages = {21--28},
     publisher = {Wolters-Noordhoff Publishing},
     volume = {20},
     year = {1968},
     mrnumber = {225637},
     zbl = {0175.26301},
     language = {en},
     url = {http://www.numdam.org/item/CM_1968__20__21_0/}
}