Scholarly, academic journal articles, books, and book chapters.
Scholarly academic journal articles and books in many disciplines.
Often the publisher contains the name of a university [ex: Oxford University Press]; if the publisher is not a university press, use Google to find the press and read about their editorial board/policies.
Sometimes these contain the word "journal" in the title; if the title does not include the word "journal," use Google to check out the journal's website & editorial board.
If the publisher is a university press, that's a good clue that the publication is peer reviewed and scholarly.