The first paper to mention the possibility of a single-dial control was Howard A. Chinn's June 1931 QST contribution, "A High Frequency Converter with Single-Dial Control." He gave constructional details but no formulas to determine the components. His method was two-point, and Gay (1979) published another paper on that subject, giving a detailed analysis and formulas. They are relatively easy compared with three-point tracking, first introduced by A. L. M. Sowerby in the Wireless Engineer & Experimental Wireless, Feb. 1932. Sowerby used the ends of the band and their arithmetic mean as the tracking points. Wald suggested bringing the outside points in from the extreme ends.
In the 1940's, numerous authors pounced on the theoretical solution of the three-point tracking problem, including A. L. Green and Ruby Payne-Scott's "Superheterodyne Tracking Charts" series, and books such as K. R. Sturley's "Radio Receiver Design," 1943, Eric E. Zepler's "The Technique of Radio Design," 1949, Frederick Emmons Terman's "Radio Engineer's Handbook," 1943, B. Sandel's article in Fritz Langford-Smith's "Radiotron Designer's Handbook," C. B. Kirkpatrick's "Three-Point Tracking Formulas," Proc. IRE, Jul 1947, and K. J. Coppin's "The Tracking of Superheterodyne Receivers," J. Brit. IRE, Nov/Dec 1948 and H. S. DeKoe's "Tracking of Superheterodyne Receivers" in Wireless Engineer, Oct. 1951.