@article{CMUC_2011_52_4_a9,
     author = {Monk, J. D.},
     title = {Maximal free sequences in a {Boolean} algebra},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {593--610},
     year = {2011},
     volume = {52},
     number = {4},
     mrnumber = {2864001},
     zbl = {1249.06034},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_2011_52_4_a9/}
}