Röbbelen, G. (1989). Oil crops of the world: Their breeding and utilization. New York: McGraw-Hill.

Röbbelen, Gerhard. Oil Crops of the World: Their Breeding and Utilization. New York: McGraw-Hill, 1989.

Röbbelen, Gerhard. Oil Crops of the World: Their Breeding and Utilization. New York: McGraw-Hill, 1989.