An evaluation of the compression strength of gypsum according to proportion and manipulation - Cardoso, Paulo Eduardo Capel; Burmann, Paulo Afonso; Anziliero, Luciano; Cardoso, Jomara Marchi Ferreira Santos; Tavares, Andréa Urbano; Sadek, Fernanda Tranchesi (Ciência Odontológica Brasiliera, 2005)