A scholarly journal article is a journal generally published through a peer-reviewed or juried process, which means that one or more scholars in the field have read and approved the article for publication. examples are the Journal of Management or the Journal of Business Ethics.
A magazine article may go through and editorial process, but it is not generally believed to be as rigorous as the peer review process. Examples are The Economist or Business Week.
A trade publication is a one usually published by and for the trade/industry itself, such as Beverage World or Marketing Week.
A newspaper is a timely news generated publication, often daily or weekly, and not necessarily unbiased. Examples include the Wall Street Journal and the New York Times.