Hill, Austin Bradford: The Environment and Disease: Association or Causation?. Proceedings of the Royal Society of Medicine, {{{Vuosi}}}, nro 58 (1965), s. 295–300. Artikkelin verkkoversio. (englanniksi)
nyu.edu
Holland, Paul W.: Statistics and Causal InferenceJournal of American Statistical Association, December 1986, Vol 81, No 396, Theory and Methods. (englanniksi)
scholarpedia.org
Seth, Anil: Granger causalityScholarpedia, Vol 2, no 7, p. 1667 (2007). (englanniksi)