Derby, Stephen J.; Anderson, Kurt; Winckler, Steven; Winckler, Jason (2006). "Motion Characteristics of a Square Wheel Car". Volume 2: 30th Annual Mechanisms and Robotics Conference, Parts A and B. Vol. 2006. Philadelphia, Pennsylvania, USA: ASME. pp. 811–816. doi:10.1115/DETC2006-99140. ISBN9780791842560.