Mares, I 2001, Firms and the welfare state: When, why, and how does social policy matter to employers?, pp. 184-213, Oxford University Press, New York.
as per the above, we need the exact two citation given there (Mares and Campbell & Petersen) formatted in your requested format to speed up the process.
It's logged; the volunteer handling these prioritizes styles for journals or scientific organizations, but it looks like the queue is pretty light, so this should happen reasonably soon.
(Campbell & Pedersen 2007)
(Mares 2001)
Bibliography:
Campbell, JL & Pedersen, OK 2007, 'The varieties of capitalism and hybrid success', Comparative Political Studies, vol. 40, no. 3, pp. 307–332. Available from: http://cps.sagepub.com.turing.library.northwestern.edu/content/40/3/307.abstract. [26 July 2010]
Mares, I 2001, Firms and the welfare state: When, why, and how does social policy matter to employers?, pp. 184-213, Oxford University Press, New York.
--Edited
https://www.zotero.org/styles?q=id:the-university-of-western-australia-harvard