Format: 

Lastname, Firstname. "Title of Case." Title of Periodical, volume, number, Day Month Year, Page(s). Case Study. Database Name or Title of Non-Publisher Website, DOI or URL.

Lastname, Firstname. Title of Case. Publisher, Year, URL or DOI (when accessed from the publisher's website). Accessed Day Month Year. Case Study.

Lastname, Firstname. "Title of Case." Title of Periodical, volume, number, Day Month Year, Page(s). Case Study.

Examples: 

Rosegrant, Susan and Dutch Leonard. Wal-Mart's Response to Hurricane Katrina: Striving for a Public-Private Partnership. Harvard Business Publishing, 28 Aug. 2007. Case Study.

In-text: (Rosegrant 3)

Suitt, Halley. "Blogger in Their Midst." Harvard Business Review, vol. 81, no. 9, Sep. 2003. Case Study. Business Source Elite, search.ebscohost.com.ezproxy.rit.edu/login.aspx?direct=true&db=bsh&AN=10687829&site=ehost-live.

In-text: (Suitt 3)

Notes: 

If the case study is published as a standalone document, cite it as you would a book (see first example). If you are using an electronic version of a case study (e.g. PDF), do not include page numbers unless you know the pages are consistent across devices (e.g. Kindle, iPad, etc.) (MLA 56). If the case study was published in a periodical (e.g. journal, magazine, newspaper), cite the case study as an article (see second example). In both instances, add Case Study at the end of the citation to indicate it is not the standard source (i.e. book or journal article). If you accessed the case study via a database, add the database name and URL after the word Case Study (see second example) (MLA 52).

Source:

This source type is not covered by the MLA Handbook (8th ed.)