@article{10_4153_CJM_1968_055_7,
     author = {Dean, R. A. and Keller, Gordon},
     title = {Natural {Partial} {Orders}},
     journal = {Canadian journal of mathematics},
     pages = {535--554},
     year = {1968},
     volume = {20},
     number = {1},
     doi = {10.4153/CJM-1968-055-7},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1968-055-7/}
}