Persson, Per-Erik, et al. “Do Non-Steroidal Anti-Inflammatory Drugs Cause Endoprosthetic Loosening? A 10-Year Follow-up of a Randomized Trial on Ibuprofen for Prevention of Heterotopic Ossification After Hip Arthroplasty”. Acta Orthopaedica, vol. 76, no. 6, Jan. 2005, pp. 735-40, doi:10.1080/17453670510045309.