Cruz, W. D. (1987). The environmental effects of soil erosion: Economic valuation issues for Philippine uplands. College of Economics and Management, University of the Philippines at Los Baños.
Lua i Stíl Chicago (17ú heag.)Cruz, Wilfrido D. The Environmental Effects of Soil Erosion: Economic Valuation Issues for Philippine Uplands. College, Laguna: College of Economics and Management, University of the Philippines at Los Baños, 1987.
Lua MLA (9ú heag.)Cruz, Wilfrido D. The Environmental Effects of Soil Erosion: Economic Valuation Issues for Philippine Uplands. College of Economics and Management, University of the Philippines at Los Baños, 1987.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.