@article{JRAM_1962__211_150558,
     author = {Barth Pollak},
     title = {4-dimensional {Orthogonal} {Groups} over {Algebraic} {Number} {Fields.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {176--178},
     publisher = {mathdoc},
     volume = {211},
     year = {1962},
     zbl = {0118.03903},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1962__211_150558/}
}