Signal your reader that the forthcoming information comes from a source -- rather than you, the researcher -- for an in-text citation: “American politicians often borrow American author Mark Twain’s most famous quote, which Twain actually used in a telegraph he sent from London in 1897: ‘The reports of my death are greatly exaggerated.’”
Create the “Works Cited” page at the end of the research paper in a double-spaced format. Make the first line of each documented source flush left and indent every subsequent line of the source five spaces.
Cite the title of author of the telegraph: “Twain, Mark.” Note the period at the end.
Provide an overview of the telegraph so that it can be identified and/or distinguished from others. In this case, “Reports of my death…” might be appropriate. Place these words in italics.
Include the city of origin and the date and/or year of the telegraph next: “London, 1897.”
Clarify the type of source; in this case, it's a telegram: "Telegram."
Put all of the information together: “Twain, Mark. Reports of my death… London, 1897. Telegram.”