1. Ángel Maya A (2015) La Fragilidad ambiental de la cultura. Historia y medio ambiente. Available at: www.augustoangelmaya.com.
2. John Paul II (1986) Humans Are Spiritual and Corporeal Beings. Available at: from https://inters.org/John-Paul-II-Catechesis-Spiritual-Corporeal.
3. John Paul II (1993) Veritatis Splendor. Available at: https://www.vatican.va/content/john-paul-ii/en/encyclicals/documents/hf_jp-ii_enc_06081993_veritatis-splendor.html.