Fotografie: Dirk J. Struik (Hamburg, 3.8.1989),  in: Joseph W. Dauben/Christoph J. Scriba (Hgg.), Writing the History of Mathematics: Its Historical Development
V. Peckhaus, Fotografie: Dirk J. Struik (Hamburg, 3.8.1989),  in: Joseph W. Dauben/Christoph J. Scriba (Hgg.), Writing the History of Mathematics: Its Historical Development, Birkhäuser, Basel/Boston/Berlin, 2002.