Higashioka Y, Kojima H, Sato S, Fukui M. Microbial community analysis at crude oil-contaminated soils targeting the 16S ribosomal RNA, xylM, C23O, and bcr genes. J Appl Microbiol. 2009 Jul;107(1):126–35. doi: 10.1111/j.1365-2672.2009.04198.x. PMID: 19298506.