Keyser, R., Rodgers, M., Gardner, E., & Russell, P. (1999). Oxygen uptake during peak graded exercise and single-stage fatigue tests of wheelchair propulsion in manual wheelchair users and the able-bodied. Archives of physical medicine and rehabilitation, 80(10), S. 1288-1292.

Keyser, R.E., M.M Rodgers, E.R Gardner, and P.J Russell. "Oxygen Uptake During Peak Graded Exercise and Single-stage Fatigue Tests of Wheelchair Propulsion in Manual Wheelchair Users and the Able-bodied." Archives of Physical Medicine and Rehabilitation 80, no. 10 (1999): S. 1288-1292.

Keyser, R.E., M.M Rodgers, E.R Gardner, and P.J Russell. "Oxygen Uptake During Peak Graded Exercise and Single-stage Fatigue Tests of Wheelchair Propulsion in Manual Wheelchair Users and the Able-bodied." Archives of Physical Medicine and Rehabilitation 80.10 (1999): S. 1288-1292.