Wilber, K., & Wilber, T. K. (2000). Grace and grit: Spirituality and healing in the life and death of Treya Killam Wilber (Second edition.). Shambhala.
Citazione stile Chigago Style (17a edizione)Wilber, Ken, e Treya Killam Wilber. Grace and Grit: Spirituality and Healing in the Life and Death of Treya Killam Wilber. Second edition. Boston: Shambhala, 2000.
Citatione MLA (9a ed.)Wilber, Ken, e Treya Killam Wilber. Grace and Grit: Spirituality and Healing in the Life and Death of Treya Killam Wilber. Second edition. Shambhala, 2000.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.