Post hoc: ergo, propter hoc is not always sound reasoning.
"The Miscellaneous Writings and Speeches of Lord Macaulay, Vol. 4 (of 4)" by Thomas Babington Macaulay
The post hoc ergo propter hoc error: he got well after taking my medicine; therefore in consequence of taking it.
"Medical Essays" by Oliver Wendell Holmes, Sr.
Post hoc, ergo propter hoc, is the motto of the savage philosophy of causation.
"Myth, Ritual, and Religion, Vol. 1" by Andrew Lang
POST HOC, ERGO PROPTER HOC.
"Sophisms of the Protectionists" by Frederic Bastiat