7.8
2011
 Stanislav Grof: Researcher, Author, Teacher, and
Stanislav Grof: Researcher, Author, Teacher, and Visionary (2011)
5.6
2002
 Hofmann's Potion: The Pioneers of LSD (2002)
Hofmann's Potion: The Pioneers of LSD (2002)
5.0
2006
 Entheogen: Awakening the Divine Within (2006)
Entheogen: Awakening the Divine Within (2006)