From The University or Wisconsin Milwaukee
In MLA Style, referring to the works of others in your text is done using parenthetical citations. This method involves providing relevant source information in parentheses whenever a sentence uses a quotation or paraphrase. Usually, the simplest way to do this is to put all of the source information in parentheses at the end of the sentence (i.e., just before the period). Use this Purdue OWL resource guide to see examples.