APA (7th ed.) Citation

Harper, R. (1991). On presence: Variations and reflections (1. publ.). Trinity Press Internat.

Chicago Style (17th ed.) Citation

Harper, Ralph. On Presence: Variations and Reflections. 1. publ. Philadelphia: Trinity Press Internat, 1991.

MLA (8th ed.) Citation

Harper, Ralph. On Presence: Variations and Reflections. 1. publ. Trinity Press Internat, 1991.

Warning: These citations may not always be 100% accurate.