@article{JRAM_1977__291_151862,
     author = {Karl Mathiak},
     title = {Projektive {Hjelmslevsche} {R\"aume} im nicht invarianten {Fall.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {182--188},
     publisher = {mathdoc},
     volume = {291},
     year = {1977},
     zbl = {0342.50015},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1977__291_151862/}
}