2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/80033The general technique of derivation of Dubrovin's equation for the arbitrary operator pencils is suggested. The question of unique recovering of the finite-gap potential by coordinates of zeroes of the Psi-function is discussed. The crucial result of the paper is an autonomous form of Dubrovin's equations and new trace-formulas for nontrivial spectral problems of the 3-rd order with trigonal algebraic curve. We show only demonstrative examples, the method is spread into arbitrary spectral problem including matrix ones.4 pages, no figuresExactly Solvable and Integrable SystemsPattern Formation and Solitonstext