The Determinant and Inverse of a Matrix on Casio Classwiz fx-991EX | fx-570EX Calculator - YouTube
Casio FX-991ES Plus Repair - iFixit
File:Vintage Casio Model fx-7000G Scientific Calculator, LCD Dot Matrix Display, Made In Japan, World's First Graphing Calculator Available To The Public, Circa 1985 - 1988 (15810483905).jpg - Wikimedia Commons
Matrices: Multiplying & Adding Matrices using your calculator Casio fx-991MS - YouTube
The Casio 991ES calculator and matrices, complex numbers, differentiation, integration, sums of series | A minimum of blind calculation