Other contributors is the fourth core element.
If someone other than the primary author (or editor) contributed to the source in a way that is relevant to your paper, you can identify that person by including this element.
Tynan, Kenneth. "The Kansas Farm Murders." The Critical Response to Truman Capote, edited by Joseph J. Waldmeir and John C. Waldmeir, Greenwood Press, 1999, pp. 129-34.
Kafka, Franz. The Metamorphosis. Translated by Stanley Corngold, 2013 ed., Modern Library, 1915.
"Something Nice Back Home." Lost, directed by Stephen Williams, performance by Matthew Fox, season 4, episode 10, Bad Robot, 2008.