Richards, L. O. (1987). A practical theology of spirituality. Zondervan Publ. House.
Citazione stile Chigago Style (17a edizione)Richards, Lawrence O. A Practical Theology of Spirituality. Grand Rapids, Mich: Zondervan Publ. House, 1987.
Citatione MLA (9a ed.)Richards, Lawrence O. A Practical Theology of Spirituality. Zondervan Publ. House, 1987.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.