The Institute for Electrical and Electronics Engineers (IEEE) is a professional organization for many facets of engineering. IEEE sets the standards for these industries. IEEE citation style uses in-text citation, which are numbered in square brackets. These refer to the full citation in the reference list at the end of the paper, which is organized numerically as opposed to alphabetically.
For more specifics, see the IEEE Editorial Style Manual.
Murdoch University has a great guide that includes many aspects of citing in IEEE style.
The American Society of Mechanical Engineers (ASME) is another professional organization for engineers. ASME also sets standards within the industry. Using in-text citations and numbering in square brackets is also expected. The numbers refer to the complete citation in the reference list, which is organized numerically and not alphabetically.
For specific examples, view the ASME website.
You can also find a detailed list of journal abbreviations here. Scroll down a bit to find the listing.
The University of Missouri also has several examples of the most common resources.