Principe W (1983). "Toward Defining Spirituality". Sciences Religieuses/Studies in Religion. ج. 12 ع. 2: 127–141. DOI:10.1177/000842988301200201.
Schnitker، Sarah (2013). "Spiritual striving and seeking the sacred: religion as meaningful goal-directed behavior". The International Journal for the Psychology of Religion. ج. 23 ع. 4: 315–324. DOI:10.1080/10508619.2013.795822.