Ruth E. Benesch, Reinhold Benesch and Chi Irg Yu, Biochemistry 8(6), 2567–2571 (1969); DOI 10.1021/bi00834a046; PMID 5799137. The publisher title and full byline identify the authors and the variables studied. The print issue is June 1969; the displayed May 2002 web posting is not the original publication date. Full text was not accessible, so no unverified experimental values or individual division of labour is attributed.