The MLA style guide calls for in-text citations to be placed inside parentheses directly after the information being cited. Enough information should be placed in the parentheses that the source can be located in the bibliography, but the nature of the information varies depending on the medium of the source.
When referencing a text source, the in-text citation generally contains the author's last name, followed by the pages on which the information is included. If the print source has no known author, an identifiable word or phrase from the title should be included instead. Sources in other media such as recordings or films may be cited using the last name of the creator or the title only.