Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) Itakura Takayasu and Matsuda Yoshinobu and Okayama Sachiko and Tohno Kaori and Hiyoshi Rie and Yoshida Kozue and Kimura Sachiko and Noma Hideki,A retrospective analysis of patients who were switched from methadone to a different opioid: How to treat cancer pain after patients become unable to take methadone orally at the end of life,Palliative Care Research,1880-5302,Japanese Society for Palliative Medicine,2015,10,4,245-250,https://cir.nii.ac.jp/crid/1390282680233112192,https://doi.org/10.2512/jspm.10.245