(1999). State of the world 1999: A worldwatch Institute report on progress toward a sustainable society. New York: Norton.
استشهاد بنمط شيكاغوState of the World 1999: A Worldwatch Institute Report On Progress Toward a Sustainable Society. New York: Norton, 1999.
MLA استشهادState of the World 1999: A Worldwatch Institute Report On Progress Toward a Sustainable Society. New York: Norton, 1999.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.