Hajnal, András; Kertesz, A. Some new algebraic equivalents of the axiom of choice. (English) Zbl 0274.04006 Publ. Math. Debr. 19(1972), 339-340 (1973). MSC: 03E25 PDFBibTeX XMLCite \textit{A. Hajnal} and \textit{A. Kertesz}, Publ. Math. Debr. 19, 339--340 (1973; Zbl 0274.04006)
Hajnal, András; Kalmár, László An elementary combinatorial theorem with an application to axiomatic set theory. (English) Zbl 0071.01005 Publ. Math. Debr. 4, 431-449 (1956). MSC: 03E30 PDFBibTeX XMLCite \textit{A. Hajnal} and \textit{L. Kalmár}, Publ. Math. Debr. 4, 431--449 (1956; Zbl 0071.01005)