Wu, Chin-Hsien, Yu-Hsien Kao, Shih-Chieh Yang, Tsai-Sheng Fu, Po-Liang Lai, and Wen-Jer Chen. 2008. “Supplementary Pedicle Screw Fixation in Spinal Fusion for Degenerative Spondylolisthesis in Patients Aged 65 and Over: Outcome After a Minimum of 2 Years Follow-up in 82 Patients”. Acta Orthopaedica 79 (1):67-73. https://doi.org/10.1080/17453670710014789.