1. Eckhard, C. (1863). Untersuchungen über die erection des penis beim hunde. Beitrage zur Anatomie und Physiologie, 3, 123–150.
2. Langley, J. N., & Anderson, H. K. (1885). The innervation of the pelvic and adjoining viscera. Part III. The external generative organs. Journal de Physiologie, 19, 85–121.
3. Henderson, V. E., & Roepke, M. H. (1933). On the mechanism of erection. The American Journal of Physiology, 106, 441–448.
4. Sjöstrand, N., & Klinge, E. (1979). Principal mechanisms controlling penile retraction and protrusion in rabbits. Acta Physiologica Scandinavica, 106, 199–214.
5. Dorr, L. D., & Brody, M. J. (1967). Hemodynamic mechanisms of erection in the canine penis. The American Journal of Physiology, 213, 1526–1531.