Taxes levied on production processes (e.g. VAT), are today a very important source of government revenues in developed economies. Theories of optimal taxation conclude that these taxes are detrimental to production efficiency, when firms operate in perfectly competitive markets. These theories...

In some cases spot markets failure to govern to whole or a part of the marketing channel effectively and contractual relations are gaining more importance. It is especially true in case of agricultural markets, since these markets became more differentiated and market players are vulnerable in...