How can I cite the quote "whatever goes upon two legs is an enemy" in Animal Farm?

In Animal Farm, Major gives a speech in Chapter 1 in which he says, "whatever goes upon two legs is an enemy" (page 8). Major is a prize-winning, old boar who shares his dreams of a better life with the other animals, who are tired of Mr. Jones's drunken dereliction of duty. Major explains to the animals on the farm that "all the evils of this life of ours spring from the tyranny of human beings" (page 7). After explaining the evils that man brings to animals, Major recounts his dream of the previous night, in which humans have disappeared from the earth and animals reign supreme. He also leads the animals in a stirring round of the song "Beasts of England," which tells of the time when beasts rule over England and man's tyranny has been overthrown. Major is supposed to represent Karl Marx, the author of the Communist Manifesto. Marx blamed the struggles of humankind on the class warfare between capitalists (or, in earlier times, the feudal lords) and the working class or proletariat, and Marx advocated a proletarian revolution against the capitalist class.

Citation: Orwell, George. Animal Farm, page 8. Signet, 1996.