Sugiharto, Henry, et al. “Efficacy of Lidocaine and Ketamine Combination on Reduction of Pain Intensity, Improvement of Functional State and Central Desensitization of Chronic Low Back Pain”. Bioscientia Medicina : Journal of Biomedicine and Translational Research, vol. 4, no. 4, Oct. 2020, pp. 45-54, https://doi.org/10.32539/bsm.v4i4.167.