Determine if the following sentence is cited correctly.

-Winston contends that Pluto should continue to be classified as a planet (12).

It is cited correctly in case that we only have one work by Winston mentioned in our bibliography page. This way, we could turn to it and see the paper or the book and find it and on page 12 we would see the quote. If there were more papers by Winston used then you would also have to add the name of the paper or the book in the brackets.