Canonical dual approach for contact mechanics problems with friction

Article later retracted; Dates are unclear - expression of concern available before issue in which it is listed (Mar 2016, vol. 21, iss. 3); See also http://retractionwatch.com/2016/01/12/math-journal-retracts-entire-issue-following-peer-review-problems/ and http://retractionwatch.com/2015/11/24/after-coordinating-peer-review-author-withdraws-special-issue-of-math-journal/;