Schlegel, Richard (1958). "Steady-State Theory at Chicago". American Journal of Physics. 26 (9): 601. doi:10.1119/1.1934713.
fortworthtexasarchives.org
The Lasso (1898). Fort Worth University. May 1898. p. 34. MacMillan was the secretary of the class of 1898 - and simultaneously an adjunct professor of astronomy.