Cram, I. A. (1972). Litter collection in country areas. Institution of Municipal Engineers.
芝加哥风格引文Cram, Ian Alexander. Litter Collection in Country Areas. London: Institution of Municipal Engineers, 1972.
MLA引文Cram, Ian Alexander. Litter Collection in Country Areas. Institution of Municipal Engineers, 1972.
警告：这些引文格式不一定是100％准确.