APA

United States, University of Puerto Rico Mayaguez Campus, . (1977). Soil survey of Arecibo area of northern Puerto Rico. Washington, D.C: Soil Conservation Service.

Chicago

United States, University of Puerto Rico Mayaguez Campus, . 1977. Soil survey of Arecibo area of northern Puerto Rico. Washington, D.C: Soil Conservation Service.

Harvard

United States, University of Puerto Rico Mayaguez Campus, . (1977). Soil survey of Arecibo area of northern Puerto Rico. Washington, D.C: Soil Conservation Service.

MLA

United States, University of Puerto Rico Mayaguez Campus, . Soil survey of Arecibo area of northern Puerto Rico. Washington, D.C: Soil Conservation Service. 1977.