@article{MS2_1968__23_166066,
     author = {T.B. Andersen and E.T. Poulsen},
     title = {On {Semi-Extremal} {Subsets} of {Convex} {Sets.}},
     journal = {Mathematica Scandinavica},
     pages = {167--168},
     publisher = {mathdoc},
     volume = {23},
     year = {1968},
     zbl = {0181.13301},
     url = {http://geodesic.mathdoc.fr/item/MS2_1968__23_166066/}
}