@article{10_1017_S2040618500035231,
     author = {Clark, W. Edwin},
     title = {Affine semigroups over an arbitrary field{\textdagger}},
     journal = {Glasgow mathematical journal},
     pages = {80--92},
     year = {1965},
     volume = {7},
     number = {2},
     doi = {10.1017/S2040618500035231},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S2040618500035231/}
}