@article{SommerKloseWelschetal.2020,
  author    = {Claudia Sommer and Petra Klose and Patrick Welsch and Frank Petzke and Winfried H{\"a}user},
  title     = {Opioids for chronic non-cancer neuropathic pain. An updated systematic review and meta-analysis of efficacy, tolerability and safety in randomized placebo-controlled studies of at least 4 weeks duration},
  journal   = {European Journal of Pain},
  volume    = {24},
  number    = {1},
  pages     = {3 -- 18},
  doi       = {10.1002/ejp.1494},
  year      = {2020},
}