Bollobás, B. An extension to the theorem of Bishop and Phelps. (English) Zbl 0217.45104 Bull. Lond. Math. Soc. 2, 181-182 (1970). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 17 ReviewsCited in 88 Documents MSC: 47A12 Numerical range, numerical radius PDFBibTeX XMLCite \textit{B. Bollobás}, Bull. Lond. Math. Soc. 2, 181--182 (1970; Zbl 0217.45104) Full Text: DOI