Zimmerman 2005b. Zimmerman, Michael E. (2005b). "Wilber, Ken (1949–)"(PDF). In Taylor, Brom R. (ed.). The Encyclopedia of Religion and Nature. Vol. 2. London: Thoemmes Continuum. pp. 1734–1744. ISBN978-1-84-706273-4. Archived from the original(PDF) on January 8, 2010. Retrieved March 21, 2021 – via www.colorado.edu.
Schneider, Kirk J. (1987). "The deified self: A "Centaur" response to Wilber and the transpersonal movement". Journal of Humanistic Psychology. 27 (3): 196–216. doi:10.1177/0022167887272006.
Schneider, Kirk J. (1989). "Infallibility is so damn appealing". Journal of Humanistic Psychology. 29 (4): 470–481. doi:10.1177/0022167889294005.
Wilber 1989. Wilber, Ken (1989). "God is so damn boring: A response to Kirk Schneider". Journal of Humanistic Psychology. 29 (4): 457–469. doi:10.1177/0022167889294004.
Rentschler 2006. Rentschler, Matt (Fall 2006). "AQAL Glossary"(PDF). AQAL: Journal of Integral Theory and Practice. 1 (3). Archived from the original(PDF) on October 12, 2011. Retrieved January 7, 2010.
Note that while Visser shows two Spiral Dynamics colors above Coral, these are not present in Beck or Cowan's publications, and Cowan explicitly states that "no colors have been assigned for nodal systems beyond Turquoise and Coral. Teal and Aubergine are candidates, but Azure and Plum also have a certain appeal." (Cowan, Christopher (2006). "FAQs > Questions About the Colors in Spiral Dynamics". Retrieved August 3, 2021.)
Zimmerman 2005b. Zimmerman, Michael E. (2005b). "Wilber, Ken (1949–)"(PDF). In Taylor, Brom R. (ed.). The Encyclopedia of Religion and Nature. Vol. 2. London: Thoemmes Continuum. pp. 1734–1744. ISBN978-1-84-706273-4. Archived from the original(PDF) on January 8, 2010. Retrieved March 21, 2021 – via www.colorado.edu.
Rentschler 2006. Rentschler, Matt (Fall 2006). "AQAL Glossary"(PDF). AQAL: Journal of Integral Theory and Practice. 1 (3). Archived from the original(PDF) on October 12, 2011. Retrieved January 7, 2010.
MacDonald 2000. MacDonald, Copthorne (2000). "Review of A Theory of Everything". Integralis: Journal of Integral Consciousness, Culture, and Science. 1. Retrieved August 12, 2020 – via Wisdompage.com.