Tupper, K. (2002) “Entheogens and Existential Intelligence: The Use of Plant Teachers as Cognitive Tools”, Canadian Journal of Education/Revue canadienne de l’éducation, 27(4), pp. 499–516. Available at: https://cje.journals.publicknowledgeproject.org/index.php/cje-rce/article/view/2843 (Accessed: 5 May 2026).