@article{CM_1988__65_2_155_0, author = {Robinson, E. Arthur}, title = {Non-abelian extensions have nonsimple spectrum}, journal = {Compositio Mathematica}, pages = {155--170}, publisher = {Kluwer Academic Publishers}, volume = {65}, number = {2}, year = {1988}, mrnumber = {932641}, zbl = {0641.28011}, language = {en}, url = {http://www.numdam.org/item/CM_1988__65_2_155_0/} }

Robinson, E. Arthur. Non-abelian extensions have nonsimple spectrum. Compositio Mathematica, Volume 65 (1988) no. 2, pp. 155-170. http://www.numdam.org/item/CM_1988__65_2_155_0/

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