APA

BROWN L., DURNING A., FLAVIN C., FRENCH H., JACOBSON J., LENSSEN N., LOWE M., POSTEL S., RENNER M., RYAN J., STARKE L. & YOUNG J. (1991). State of the World. New York: Worldwatch Institute.

Chicago

BROWN Lester.R, DURNING Alan, FLAVIN Christopher, FRENCH Hilary, JACOBSON Jodi, LENSSEN Nicholas, LOWE Marcia, POSTEL Sandra, RENNER Michael, RYAN John, STARKE Linda and YOUNG John. 1991. State of the World. New York: Worldwatch Institute.

Harvard

BROWN L., DURNING A., FLAVIN C., FRENCH H., JACOBSON J., LENSSEN N., LOWE M., POSTEL S., RENNER M., RYAN J., STARKE L. and YOUNG J. (1991). State of the World. New York: Worldwatch Institute.

MLA

BROWN Lester.R, DURNING Alan, FLAVIN Christopher, FRENCH Hilary, JACOBSON Jodi, LENSSEN Nicholas, LOWE Marcia, POSTEL Sandra, RENNER Michael, RYAN John, STARKE Linda and YOUNG John. State of the World. New York: Worldwatch Institute. 1991.