Johnny Sokko and His Flying Robot V. 4 [VHS] : Various: Movies & TV - Amazon.com
Review - Robot Ninja (1989) + J. R. Bookwalter interview // VHS - YouTube
Blu-Ray Review: VHS-Era Shocker "Robot Ninja" Gets Back In Fighting Shape - Rue Morgue
Amazon.com: Robot Ninja : J.R. Bookwalter, Michael Todd, Bogdan Pecic, Maria Markovic, Burt Ward, Linnea Quigley, J.R. Bookwalter, Scott P. Plummer, David DeCoteau, J.R. Bookwalter: Movies & TV