Printed Sources   Printed Materials Part of a book 1. John Murray. "Biology" D. G. Mackean, 1995, pp. 198-210 2. Campbell Reece Mitchell. "Biology" Addison Wesley Longman, 1999, pp. 224-388   Printed Materials Entire book 1. Burke K. Zimmerman. "Biofuture Confronting the Genetic Era" Plenum Press. New York and London, 1984 2. Gordon Rattray Taylor. "The Biological Time Bomb" The New American Library, 1968