Look at the publisher. A refereed journal ( say, the American Historical Review, put out by the American Historical Association) will have peer-reviewed articles.

For books, an academic publisher , like the Oxford University Press, will publish peer-reviewed books. The AHR and other scholarly journals will also themselves publish critical reviews of recent books- often those can be found through searches on JSTOR.

Note that at the bottom of the first page of the article you will often- very often- discover something like "the author(s) would like to thank Dr. Conrad Zittwitz of the Dresden Meteorological Museum for reading this article and making useful comments". If Dr. Zittwitz is a leading scholar in the field, that does give the article more credence. BUT if authors can pick their own reviewers, there's always a danger that they'll simply ask someone they know will already agree with them...which is not how real peer review works.