Discourses of the Popes from Pius XI to John Paul II to the Pontifical Academy of Sciences : 1936-1986. - Haffner, Paul, sac. (OLS)http://pul/name/2119; Pontificia Accademia delle scienze. (OLS)http://pul/name/1110 (ex Aedibus Academicis, 1986)
"English version edited by Fr. Paul Haffner".