If you are writing an essay about Oedipus Rex, it is worth referring to the huge influence that Sophocles' play has had upon later literature. Many, many plays, films and books have drawn upon the story of Oedipus, and some of them might make excellent comparison. A short, and by no means exhaustive, list of such works is below.
Aeschylus, The Oresteia (458 BC).
Seneca, Oedipus (first century CE).
Shakespeare, King Lear (c.1605).
Shakespeare, Hamlet (c.1600).
Shakespeare, Macbeth (c.1605).
Jean Cocteau, The Infernal Machine (1934).
Arthur Miller, All My Sons (1947).
Steven Berkoff, Greek (1980).
Edward Albee, The Goat (2002).
You should also read Sophocles' sequel to Oedipus Rex, composed at the very end of his life, Oedipus at Colonos.
You might also, for a more humorous perspective, look at Tom Lehrer's song Oedipus Rex (1959).
