Calabi, Lorenzo Sur les extensions des groupes topologiques. (French) Zbl 0054.01302 Ann. Mat. Pura Appl., IV. Ser. 32, 295-370 (1951). PDFBibTeX XMLCite \textit{L. Calabi}, Ann. Mat. Pura Appl. (4) 32, 295--370 (1951; Zbl 0054.01302) Full Text: DOI
Gelbaum, B.; Kalisch, G. K.; Olmsted, J. M. H. On the embedding of topological semigroups and integral domains. (English) Zbl 0045.00801 Proc. Am. Math. Soc. 2, 807-821 (1951). PDFBibTeX XMLCite \textit{B. Gelbaum} et al., Proc. Am. Math. Soc. 2, 807--821 (1951; Zbl 0045.00801) Full Text: DOI
Montgomery, Deane; Zippin, Leo Two-dimensional subgroups. (English) Zbl 0044.25901 Proc. Am. Math. Soc. 2, 822-838 (1951). PDFBibTeX XMLCite \textit{D. Montgomery} and \textit{L. Zippin}, Proc. Am. Math. Soc. 2, 822--838 (1951; Zbl 0044.25901) Full Text: DOI
Mautner, F. I. On the decomposition of unitary representations of Lie groups. (English) Zbl 0043.03001 Proc. Am. Math. Soc. 2, 490-496 (1951). PDFBibTeX XMLCite \textit{F. I. Mautner}, Proc. Am. Math. Soc. 2, 490--496 (1951; Zbl 0043.03001) Full Text: DOI