Unique local existence of solution in low regularity space of the Cauchy problem for the mKdV equation with periodic boundary condition Kenji Nakanishi, Hideo Takaoka, Yoshio Tsutsumi (2007/2008) Séminaire Équations aux dérivées partielles
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Uniqueness in a one-dimensional problem of finding a time-dependent potential. Dyatlov, G.V. (2001) Siberian Mathematical Journal