 Popa's writings on science, culture and ideology were published by his descendants as "Reforma Spiritului" ("Spiritual Reform") in 2002.Other essays were collected by physician Richard Constantinescu in a 2008 volume of works by and about Ion Petrovici.This is one of several monographs and anthologies edited by Constantinescu, detailing such topics as Popa's Christian faith and his correspondence with poet-physician Vintilă Ciocâlteu, and including his American diary (published 2014).