When using MLA format, use the shortest piece of information that directs the reader to the entry in the works-cited list. This can be done in either prose or parenthetical form. The shortest piece of information is usually the author's surname or (if there is no author named) the shortened title of the work. Additional information will be needed in order to:
Works referenced in text should correspond to entries your works cited list.
If you are making reference to an entire book, article, or other work, you only have to make reference to the author in your in-text reference. This also applies to works that are a single page in length.
(Black)
If you are directly quoting or paraphrasing a specific part of a a work, you will need to include the author and the page number or other location information for the reference. Do NOT precede page numbers with p. or pp. If citing a number other than a page number, precede it with a label (such as chapter, line, section, or scene). In parenthetical citation, abbreviations are generally used for chapters, sections, and scenes (ch., sec., and sc.), but not for lines.
According to Brady Lund, while asynchronous communication creates certain forms of anxiety, "generally greater levels of anxiety are experienced with synchronous (real-time) communication" (59).
OR: While asynchronous communication creates certain forms of anxiety, "generally greater levels of anxiety are experienced with synchronous (real-time) communication" (Lund 59).
If you are including the citation as part of the prose of your paper, you don't have to put an additional citation at the end of your sentence, unless you are paraphrasing or quoting from a particular page or page range, in which case put the page number(s) in parentheses.
Ian Smith found . . . (147).