APA (7th ed.) Citation

Allen, C. E. (1969). Machinery's screw thread book (20th ed.). Machinery Publishing.

Chicago Style (17th ed.) Citation

Allen, Clarence Edgar. Machinery's Screw Thread Book. 20th ed. London: Machinery Publishing, 1969.

MLA (8th ed.) Citation

Allen, Clarence Edgar. Machinery's Screw Thread Book. 20th ed. Machinery Publishing, 1969.

Warning: These citations may not always be 100% accurate.