Additions to the articles in the September number of this journal, ”On a new class of theorems,” and on Pascal’s theorem. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 1850, 37. vsk, s. 363–370. Taylor & Francis. Artikkelin verkkoversio. Viitattu 20.1.2018.
The Collected Mathematical Papers of James Joseph Sylvester: 1837–1853, s. 247. (Paper 37) American Mathematical Society, 2005. Teoksen verkkoversio (viitattu 20.1.2018).