(740 ILCS 160/11) (from Ch. 59, par. 111)
    Sec. 11. Unless displaced by the provisions of this Act, the principles of law and equity, including the law merchant and the law relating to principal and agent, estoppel, laches, fraud, misrepresentation, duress, coercion, mistake, insolvency, or other validating or invalidating cause, supplement its provisions.
(Source: P.A. 86-814.)