Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) ANDREWS CJH.,The additive effect of nitrous oxide on respiratory depression in patients having fentanyl or alfentanil infusions,Br J Anaesth,,,1982,54,,1129,https://cir.nii.ac.jp/crid/1570291224651529984,