Coudane, H., et al. “Aseptic Loosening of Cemented Total Arthroplasties of the Hip in Relation to Positioning of the Prosthesis: New Utilization of the Tschuprow-Cramer Statistical Test”. Acta Orthopaedica, vol. 52, no. 2, Jan. 1981, pp. 201-5, doi:10.3109/17453678108991782.