Per Christiansen 
Research associate at the Zoological Museum in Copenhagen, specialising in biomechanics and terrestrial locomotion in mammals and dinosaurs.
Bonde, N., and Christiansen, P., 2003, The detailed anatomy of Rhamphorhyhchus: axial pneumaticity and its implications: In: Evolution and Palaeobiology of Pterosaurs, edited by Buffetaut, E., and Mazin, J.-M., Geological Society Special Publication, n. 217, p. 217-232.