It's not your father's MLA style guide anymore (or your mom's)
Even in citations, print is the default no more. The seventh edition of the MLA Handbook for Writers of Research Papers, released Tuesday, states that the Modern Language Association no longer recognizes print as the default medium, and suggests that the medium of publication should be included in each works cited entry.
Moreover, the MLA has ceased to recommend inclusion of URLs in citing Web-based works – unless the instructor requires it or a reader would likely be unable to locate the source otherwise. “Inclusion of URLs has proved to have limited value… for they often change, can be specific to a subscriber or a session of use, and can be so long and complex that typing them into a browser is cumbersome and prone to transcription errors. Readers are now more likely to find resources on the Web by searching for titles and authors' names than by typing URLs,” states the handbook.
Read entire article at Inside Higher Ed
Moreover, the MLA has ceased to recommend inclusion of URLs in citing Web-based works – unless the instructor requires it or a reader would likely be unable to locate the source otherwise. “Inclusion of URLs has proved to have limited value… for they often change, can be specific to a subscriber or a session of use, and can be so long and complex that typing them into a browser is cumbersome and prone to transcription errors. Readers are now more likely to find resources on the Web by searching for titles and authors' names than by typing URLs,” states the handbook.