I am not sure what you are trying to do here. Oman is the main author in most of them. I count ten papers cited, all dating to 2006-2009 with one exception (2003), and Oman is listed as author in ten out of ten papers, with varying co-authors. This means that there is one group of authors churning out papers on PM, "publish or perish" style. Any evidence that these papers had any kind of impact, or is this the academic equivalent of writing to /dev/null?  (𒁳)