Elmerson, S., Andersson, G. B. J., Irstam, L., & Zetterberg, C. (1988). Internal fixation of femoral neck fracture: No difference between the Rydell four-flanged nail and Gouffon’s pins. Acta Orthopaedica, 59(4), 372–376. https://doi.org/10.3109/17453678809149384