Breuning Madsen, H. 1985. Plant production and management under drought conditions: papers presented at the symposium, 4-6 October 1982, held at Tulsa, OK, U.S.A. Ed. by John F. Stone, Wayne O. Willis. - (Developments in agricultural and managed-forest ecology, 12). Geografisk Tidsskrift. 85, (jan. 1985).