Cita APA

Gray, T. R., & Timothy, R. (1977). Soil micro-organisms. London, Sydney: Longman.

Citación estilo Chicago

Gray, Timothy R.G, y R.T Timothy. Soil Micro-organisms. London, Sydney: Longman, 1977.

Cita MLA

Gray, Timothy R.G, y R.T Timothy. Soil Micro-organisms. London, Sydney: Longman, 1977.