APA引文

Blokhuis, W. A. (1993). Vertisols in the central clay plain of the Sudan. s.n..

Chicago Style (17th ed.) Citation

Blokhuis, W. A. Vertisols in the Central Clay Plain of the Sudan. [Netherlands?: s.n., 1993.

MLA引文

Blokhuis, W. A. Vertisols in the Central Clay Plain of the Sudan. s.n., 1993.