Editors. "Mathieu Dreyfus discovers that Major Esterhazy convicted his brother". The Literary Encyclopedia. First published 30 December 2011
[http://www.litencyc.com/php/stopics.php?rec=true&UID=19236, accessed 06 December 2013.]
Alfred Dreyfus's elder brother, Mathieu, who has supported him throughout his false conviction for treason, establishes through handwriting analysis that the letter on the evidence of which his brother was convicted was actually written by Major Ferdinand Esterhazy.