“Effect of Low Dose Naltrexone Versus Naproxen Extended-Release for Pain Relief in Knee Osteoarthritis, a Triple-Blinded, Non-Inferiority Phase II Randomized Controlled Trial (FREEDOM) - Study Protocol”. Principles and Practice of Clinical Research, vol. 7, no. 1, May 2021, https://doi.org/10.21801/ppcrj.2021.71.3.