Matrices and Complex Numbers: Problem Solving using the Casio fx-991ES Calculator (Cambridge Paperbacks A Level Maths Series) - Brown, Allen: 9780993591723 - AbeBooks
Casio FX-991EX Classwiz Non-Programmable Scientific Calculator, 552 Functions with Menu Driven Interface, Black : Amazon.in: Office Products
Quick Start Guide (fx 991EX/fx570EX)_CASIO All CASIO Fx 991EX 570EX
fx-991EX - Casio Calculators
How to find the Square Root of a complex number | Casio fx - 991es/ plus - YouTube