Hellwig, K.-E.; Kraus, K. Operations and measurements. II. (English) Zbl 0186.28204 Commun. Math. Phys. 16, 142-147 (1970). PDF BibTeX XML Cite \textit{K. E. Hellwig} and \textit{K. Kraus}, Commun. Math. Phys. 16, 142--147 (1970; Zbl 0186.28204) Full Text: DOI
Hellwig, K.-E.; Kraus, K. Pure operations and measurements. (English) Zbl 0165.58302 Commun. Math. Phys. 11, 214-220 (1969). MSC: 81-XX PDF BibTeX XML Cite \textit{K. E. Hellwig} and \textit{K. Kraus}, Commun. Math. Phys. 11, 214--220 (1969; Zbl 0165.58302) Full Text: DOI