Παραπομπή APA
(1979). Directory of scientific directories: A world guide to scientificdirectories including medicine, agriculture, engineering, manufacturing and industrial directories (Third edition.). Essex: Longman Group Limited.
Παραπομπή Chicago StyleDirectory of Scientific Directories: A World Guide to Scientificdirectories Including Medicine, Agriculture, Engineering, Manufacturing and Industrial Directories. Third edition. Essex: Longman Group Limited, 1979.
Παραπομπή MLADirectory of Scientific Directories: A World Guide to Scientificdirectories Including Medicine, Agriculture, Engineering, Manufacturing and Industrial Directories. Third edition. Essex: Longman Group Limited, 1979.
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