@article{SF_1975__11_134142,
     author = {H. J\"urgensen},
     title = {Vereinigungserweiterungen durch vollst\"andig 0-einfache {Halbgruppen.}},
     journal = {Semigroup forum},
     pages = {185--188},
     publisher = {mathdoc},
     volume = {11},
     year = {1975},
     zbl = {0334.20033},
     url = {http://geodesic.mathdoc.fr/item/SF_1975__11_134142/}
}