M. Arrieta, J., A. Rodriguez-Bernal, and P. Souplet. “Boundedness of Global Solutions for Nonlinear Parabolic Equations involving Gradient Blow-up Phenomena”. ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE, vol. 3, no. 1, Dec. 2009, pp. 1-15, doi:10.2422/2036-2145.2004.1.01.