“Bibliographic negligence” aka "citation amnesia”
An editorial in The Scientist (free, but registration required to access) discusses this rather shady practice- ie of failing to cite relevant papers. The writer, Richard Gallagher, raises an interesting point that“the openness gifted us by the Internet is revealing the lax standards that have been in place all the time. “- one that could easily be made of many other dubious publication practices.
But as he notes “What's new about these [new] cases is that they're being played out online in full gory detail and in real time.” He discussed two recent cases and calls for “a code of practice for citation, which journals should adopt explicitly” There is also a poll on this topic.