It's important to cite sources you used in your research for several reasons:
Jacobs, Alan. The Pleasures of Reading in an Age of Distraction. Oxford UP, 2011.
In this version, only the most essential information is included (author’s name, book title, publisher, and date). Note that the city of publication is not needed, and the medium of publication is eliminated.
Article from a Scholarly Journal
Kincaid, Jamaica. “In History.” Callaloo, vol. 24, no. 2, Spring 2001, pp. 620-26.
This version identifies the volume (24), the number (2), and the page numbers (620-26) of the scholarly journal, rather than leaving those numbers without clear explanation. This helps readers best make sense of your citation and allows them to locate your source without getting bogged down with extra information or references that can be difficult to decipher. Also note that punctuation is simple; only commas separate the journal title, volume, number, date, and page numbers.