Philippines (Republic) Bureau of Soil Conservation. Soil erosion. Office of Agricultural Information.
芝加哥风格引文Philippines (Republic) Bureau of Soil Conservation. Soil Erosion. [Manila: Office of Agricultural Information.
MLA引文Philippines (Republic) Bureau of Soil Conservation. Soil Erosion. Office of Agricultural Information.
警告：这些引文格式不一定是100％准确.