<https://pubs.asahq.org/anesthesiology/issue/96/4>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://pubs.asahq.org/anesthesiology/article/96/4/NA/42931/POOLED-ANALYSIS-OF-RANDOMIZED-TRIALS-OF-EPIDURAL>