APA (7th ed.) Citation

Unsworth, J. F., Barratt, D. J., & Roberts, P. T. (1991). Coal quality and comustion performance: An international perspective. Shell Research.

Chicago Style (17th ed.) Citation

Unsworth, John F., David J. Barratt, and Peter T. Roberts. Coal Quality and Comustion Performance: An International Perspective. Amserdam: Shell Research, 1991.

MLA (8th ed.) Citation

Unsworth, John F., et al. Coal Quality and Comustion Performance: An International Perspective. Shell Research, 1991.