APA (7th ed.) Citation

Lessing, R. (1931). Clean coal in the gas industry. Gas Journal, 194, 821.

Chicago Style (17th ed.) Citation

Lessing, R. "Clean Coal in the Gas Industry." Gas Journal 194 (1931): 821.

MLA (9th ed.) Citation

Lessing, R. "Clean Coal in the Gas Industry." Gas Journal, vol. 194, 1931, p. 821.

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