APA Style originated in 1929, when a group of psychologists, anthropologists, and business managers convened and sought to establish a simple set of procedures, or style rules, that would codify the many components of scientific writing to increase the ease of reading comprehension. As with other editorial styles, APA Style consists of rules or guidelines that a publisher observes to ensure clear and consistent presentation of written material.
MLA style is a system for documenting sources in scholarly writing. For over half a century, it has been widely adopted for classroom instruction and used throughout the world by scholars, journal publishers, and academic and commercial presses.
IEEE Style is a standard of the Institute of Electrical and Electronics Engineers and is used for research papers in some technical fields such as electrical engineering, computer science, and computer engineering.