Rerum Novarum
Sollicitudo Rei Socialis
Quadragesimo Anno
Mater et Magistra
Gaudium et Spes
Libertatis Conscientia
Octogesima Adveniens
Laborem Exercens
Pacem in Terris
Official Church Summarizations
Catechism https://www.usccb.org/sites/default/files/flipbooks/catechism/462/
Compendium of the Social Doctrine of the Church https://www.vatican.va/roman_curia/pontifical_councils/justpeace/documents/rc_pc_justpeace_doc_20060526_compendio-dott-soc_en.html#Origin%20and%20meanin
Mentions around the Web
Catholic Culture quoting This Rock https://www.catholicculture.org/culture/library/view.cfm?id=7538#PartV