The governments of Burkina Faso and Sierra Leone have started to negotiate with wholesalers to control prices indirectly. 布基纳法索和塞纳里昂政府已经开始与批发商协商，以此间接控制粮价。
The absolute stability of a class of indirect control systems by applying the theory of Hermitian quadratic form and Jordan normal form was studied. 利用厄米特二次型和若当标准形理论研究了一般间接控制系统的绝对稳定性问题，给出了绝对稳定性的代数形式的判别准则。
