Laura Geggel, Oddball Philosopher Had His Mummified Body Put on Display … and Now His Rings Are Missing, in Live Science, 11 settembre 2018. URL consultato il 26 marzo 2019.
«"We can safely assume that [Guatemalan philosopher and politician] José del Valle received one, as he is featured wearing it in a portrait," Causer said. "Interestingly, on the bookshelf of that portrait is one of Bentham’s works, as well as a Spanish translation of Say’s 'Traité d’économie politique.' It’s a neat, tangible link between Bentham, Say and del Valle."»
