http://www.jogg.info/32/campbell.htm
Oppenheimer and Sykes are rarely mentioned these days ,unless it's in negative terms about the early days of the research . Because of the rate of change in info books are few and far between, part of the problem with O and S was that as soon their books were out papers had refuted them with new info . O and S could be likened to early antiquarians attempting to date monuments and coming up with druid altars and Mycenaean temples , possibly a bit extreme but you get the idea .
It's nearly all papers, the archaeo stuff is limited but, the snippets keep coming . The amateur experts are also providing important findings , this is due to punters getting their DNA done and investigating similar findings to their own with the freely available info on genome sequences , which has resulted in new discoveries of branches of particular haplotypes that would have usually been the work of the pros .