Weak separability in coffee demand systems
估计美国和德国咖啡进口的线性几乎理想需求系统，检验同质和非同质弱可分性，发现可分性限制被拒绝，且不同来源国咖啡的弹性显示既有替代也有互补关系。
Linear versions of the Almost Ideal Demand System are estimated for US and German coffee imports with the intent of testing for homothetic and non-homothetic weak separability and calculating elasticities. Three different separable groupings are tested and separability restrictions are rejected. Elasticities indicate both elastic and inelastic demand for coffee by country of origin, and also that roasters consider such coffees as both substitutes and complements.