(en) Samuel Harden, History of Madison County, Indiana, From 1820 to 1874 : giving a general review of principal events, statiscal and historical items, derived from official sources, Markleville, , 417 p. (lire en ligne), p. 2.
(en) James A. Glass, « The Gas Boom in East Central Indiana », Indiana Magazine of History, Indiana University Press, vol. 96, no 4, , p. 313-335 (lire en ligne, consulté le ).