‎"SANDBERG, I. W.‎
‎Some Results on the Theory of Physical Systems Governed by Nonlinear Functional Equations. - [PROPERTIES OF SOLUTIONS IN PHYSICAL SYSTEMS]‎

‎New York, American Telephone and Telegraph Company, 1965. 8vo. Volume XLIV, Number 5, May-June 1965 of ""The Bell System Technical Journal"". Entire volume offered. In the original printed blue wrappers. With previous owner's name stamped to front wrapper. Sunning to spine and margins of front wrapper. An overall nice and clean copy. Pp. 871-898. [Entire volume: Pp. 731-935 + one folded diagram].‎

Reference : 43507

‎First publication of Sandberg's first paper on the properties of solutions of nonlinear functional equations in physical systems.""With a few exceptions, however, the users of linear theory, when faced with the presence of a nonlinear element, were forced either to fall back on the classical technique of analyzing the stability of system only under small perturbations, or else to treat the nonlinearity itself as a small perturbation. In a SEMINAL SEQUENCE OF PAPERS beginning in 1963 [the present paper being the first publication], I. W. Sandberg at Bell Labs set forth a full analysis, not limited to small perturbations, of the stability of feedback systems containing nonlinear elements of a precisely specified kind."" (Millman, S. A History of Engineering & Science in the Bell System, 1984, p. 31).‎