(2002) [Toufigh قام بدراسة مسائل الجريان حيث قام بفرض بان معاملات النفاذية ثابتة في معادلة لابلاس مع الفراغ والزمن و لكن بالواقع الحقلي تكون تلك القيم متغيرة
(2002) [Toufigh studied runoff where he imposed that the constant permeability coefficients in the Laplace equation with the space and time issues, but the reality field are those variable values
(2002) [Toufigh) studied the issues of flux where he imposed that the permeability coefficients are constant in the laplace equation with space and time, but in reality these values are variable.