The IEEE is a type of numbered referencing style. In IEEE all the in-text citations receive a number. The references are given in numerical order in the appearance they make in the work. That number is repeated in the in-text citation each time the same reference is used. A reference list is then displayed at the end of the article with the full details of all references that have been cited in-text.
Example of using a number in-text:
The desire for artificial intelligence to display human qualities is often depicted in science fiction, for example, the character Data who wishes to acquire the ability to experience emotions .
Example of citing journal article in the reference list:
 S. Short, "The Measure of a Man? Asimov's Bicentennial Man, Star Trek's Data, and Being Human," Extrapolation, vol. 44, no. 2, pp. 209-223, 2003. doi: 10.3828/extr.2003.442.6
The Chicago Author-Date referencing style has two basic systems of documentation:
A numeric citation system, commonly used in medical and scientific journals.
Referencing in Vancouver Citation Style requires:
The definitive guide to Vancouver referencing was developed by the National Library of Medicine in the US. The others are examples from other university libraries. Each are slightly different so it is important to be consistent with whichever version you follow.