APA (7th ed.) Citation

Mathur, R. B., Lal, C., & Sharma, D. K. (2007). Catalyst-Free Carbon Nanotubes from Coal-Based Material. Energy Sources, 29, 21.

Chicago Style (17th ed.) Citation

Mathur, R. B., C. Lal, and D. K. Sharma. "Catalyst-Free Carbon Nanotubes from Coal-Based Material." Energy Sources 29 (2007): 21.

MLA (9th ed.) Citation

Mathur, R. B., et al. "Catalyst-Free Carbon Nanotubes from Coal-Based Material." Energy Sources, vol. 29, 2007, p. 21.