1. Adaptive Riding Institute (2011). Adaptive equipment. Retrieved February 27, 2011, from http://www.adaptiveridinginstitute.org/ariequipment.html .
2. American Hippotherapy Association (AHA) (2010a). Hippotherapy as a treatment strategy. Retrieved February 22, 2012, from http://www.americanhippotherapyassociation.org./hippotherapy/hippotherapy-as-a-treatment-strategy/
3. American Hippotherapy Association (AHA) (2010b). History of Hippotherapy. Retrieved February 22, 2012, from http://www.americanhippotherapyassociation.org/hippotherapy/history-of-hippotherapy/
4. Bass, M. M., Duchowny, C. A., & Llabre, M. M. (2009). The effect of therapeutic horseback riding on social functioning in children with autism. Journal of Autism and Developmental Disorders, 39, 1261–1267.
5. Benzies, K. M., Premji, S., Hayden, K. A., & Serrett, K. (2006). State of evidence reviews: advantages and challenges of including grey literature. Worldviews on Evidence-Based Nursing, 3, 55–61.