The following is the Elsevier retraction statement that will appear shortly.
This article has been retracted at the request of the Editor in Chief and co‑Editors, as it contain portions of other authors' writings on the same topic in other publications, without sufficient attribution to these earlier works being given.
The principal authors of the paper acknowledged that text from background sources was mistakenly used in the Introduction without proper reference to the original source.
Specifically, the first page and a half of the article (pp. 2177‑2178) contain together excerpts from Wikipedia (first paragraph), Wasserman and Faust's "Social Network Analysis: Methods and Applications" (pp. 17‑20) ISBN 10: 0521387078 / 0‑521‑38707‑8 ISBN 13: 9780521387071 Publication Date: 1994, and W. de Nooy, A. Mrvar, and V. Bategelj's "Exploratory Social Network Analysis with Pajek" (pp. 31, 36, 123, and 133) ISBN 10: 0521602629 / 0‑521‑ 60262‑ ISBN 13: 9780521602624 Publication Date: 2005.
The scientific community takes a strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process. One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. The re‑use of material, without appropriate reference, even if not known to the authors at the time of submission, breaches our publishing policies.
There is also some information in this story on the Bradley complaint:
Bradley has complained to Elsevier, which was the publisher of the 1999 book, and company officials have proposed a meeting to discuss the issue, he says. "Elsevier has a financial interest in people not plagiarizing their books," says Bradley. "Otherwise, why do they have a copyright?"
Some background here.