Uniqueness for the harmonic map flow from surface to general targets. Alexandre Freire (1995) Commentarii mathematici Helvetici
Uniqueness of nonnegative solutions of the Cauchy problem for parabolic equations on manifolds or domains Kazuhiro Ishige, Minoru Murata (2001) Annali della Scuola Normale Superiore di Pisa - Classe di Scienze