Lorenzi, Luca. “Estimates of the Derivatives for a Class of Parabolic Degenerate Operators With Unbounded Coefficients in R<sup>N</Sup> ”. ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE 4, no. 2 (December 4, 2009): 255-293. Accessed May 28, 2025. http://20.103.181.36/index.php/annaliscienze/article/view/68.