英文文献：A study of the demand relationship between fixed-weight and random-weight citrus-柑橘固定重量与随机重量之间需求关系的研究
英文文献作者：Gao, Zhifeng,Lee, Jonq-Ying,Brown, Mark G.
英文文献摘要：
Using Rotterdam demand system this study examines the demand relationships among four random-weight (FW) and fixed-weight citrus (RW). Results indicated that FW and RW grapefruit (and FW and RW oranges) are not substitutes; however, RW tangerine is a substitute of FW tangerines. In addition, promoting FW grapefruit would not influence the demand for RW grapefruit and vice versa. Promoting FW oranges (or FW tangerines) would decrease the demand for RW oranges (or RW tangerines) and vice versa.

本研究利用鹿特丹需求系统研究了4种随机重量柑橘与定重柑橘之间的需求关系。结果表明，FW和RW葡萄柚(和FW和RW橙子)不是替代品;然而，RW橘子是FW橘子的替代品。另外，推广FW葡萄柚不会影响RW葡萄柚的需求，反之亦然。推广FW橙(或FW橘子)会减少RW橙(或RW橘子)的需求，反之亦然。