Catholic Church. Pope (1963-1978 : Paul VI), Pope Paul VI (1976). “On evangelization in the modern world: Apostolic exhortation Evangelii nuntiandi, December 8, 1975”
G. Stanley Hall (2013). “Adolescence - Its Psychology and Its Relations to Physiology, Anthropology, Sociology, Sex, Crime, and Religion (1931)”, p.9, Read Books Ltd
Rudyard Kipling (2016). “Collected Works of Rudyard Kipling (Illustrated Edition): 5 Novels & 350+ Short Stories, Poetry, Historical Military Works and Autobiographical Writings from one of the most popular writers in England, known for The Jungle Book, Kim, The Man Who Would Be King”, p.66, e-artnow (Open Publishing)