Lessing, Hans-Erhard (1997). The evidence against Leonardo's bicycle. 8th International Conference on Cycling History. San Francisco. pp. 49–56. Retrieved 24 April 2023 – via cyclepublishing.com.
UK 3531, Hughes, John Henry, "Improvements in the bearings of bicycles and velocipedes or carriages (No. 3531, filed 1877-09-19, published 1877-10-12)", published 1877-10-12
UK 3531, Hughes, John Henry, "Improvements in the bearings of bicycles and velocipedes or carriages (No. 3531, filed 1877-09-19, published 1877-10-12)", published 1877-10-12