Experiencing the risk of overutilising opioids among patients with chronic non-cancer pain in ambulatory care (ERONA): the protocol of an exploratory, randomised controlled trial
O Wegwarth, C Spies, E Schulte, J J Meerpohl, C Schmucker, E Nury, D Brockmann, N Donner-Banzhoff, S Wind, E Goebel, W-D Ludwig, R Hertwig