1. Gale E. Christianson, Edwin Hubble: Mariner of the Nebulae, (University of Chicago Press 1995), pgs. 81-83
2. Ibid. pg. 62
3. A Brief History, (The Queen’s College University of Oxford), Retrieved April 21st, 2020, https://www.queens.ox.ac.uk/history
4. Sir Christopher Wren, BBC History Page, Retrieved April 21st, 2020, https://www.bbc.co.uk/history/historic_figures/wren_christopher.shtml
5. Gale E. Christianson, Edwin Hubble: Mariner of the Nebulae, (University of Chicago Press 1995), pgs. 65-77