H. Sugiharto, Hasnawi Haddani, Yuki Fitria, and Rizal Zainal, “Efficacy of Lidocaine and Ketamine Combination on Reduction of Pain Intensity, Improvement of Functional State and Central Desensitization of Chronic Low Back Pain”, Bioscmed, vol. 4, no. 4, pp. 45-54, Oct. 2020.