APA (7th ed.) Citation

Hopkins, G. R. (1927). Some economic phases of carbon black industry. [publisher not identified].

Chicago Style (17th ed.) Citation

Hopkins, G. R. Some Economic Phases of Carbon Black Industry. Washington, D.C.: [publisher not identified], 1927.

MLA (9th ed.) Citation

Hopkins, G. R. Some Economic Phases of Carbon Black Industry. [publisher not identified], 1927.