APA (7th ed.) Citation

Ahmed, O. H., Kasim, S., & Nik Ab. Majid, N. M. (2009). Method of isolating humic acid.

Chicago Style (17th ed.) Citation

Ahmed, Osumanu Haruna, Susilawati Kasim, and Nik Muhamad Nik Ab. Majid. Method of Isolating Humic Acid. 2009.

MLA (9th ed.) Citation

Ahmed, Osumanu Haruna, et al. Method of Isolating Humic Acid. 2009.