There are many style guides available. When working on a bibliographies, follow your professor's instructions on the assignment they have given you. If they have not given you instructions about which style guide to use you can choose a style guide. ACS (American Chemical Society) and AIP (American Institute of Physics) have more technical examples and are used more in engineering than APA (American Psychological Asssociation), Chicago, MLA (Modern Languages Association), and Turabian. One of the best online sites for basic citiation style in ALA or MLA formats is run by Purdue University's Online Writing Lab (OWL).
Citation managers are software that keep track of your sources and automatically format your citations in a variety of styles.
