Journal Articles: Peer-reviewed journals are written by academic experts in business topics (MBA's, PhD's) and reviewed by other experts in the field. Might focus on a topic overall, or may be a case study on a particular business.
Trade Journal Articles: Trade journals are highly specialized publications written by people working in or academically involved in a particular industry. They often provide in-depth information on trends, new products and other topics of interest to people working in that industry. Some are peer-reviewed, and some are not.
Newspaper Articles: Newspapers are written by journalists and are published frequently. They are not peer-reviewed. They report on current events and have up to date information.
Magazine Articles: A published periodical that contains a collections of texts such as essays, articles and stories. They are not generally peer-reviewed, and are written mostly by journalists.