Amazon.com: ALAMSCN MAX7219 Dot Matrix Module 32x8 4 in 1 LED Display Modules for Arduino Raspberry Pi Microcontroller with 5Pin Wires Green (Pack of 2) : Industrial & Scientific
HCDotMatrix Arduino library for 8x8 LED dot matrix module - forum.hobbycomponents.com
Arduino Matrix Display 8 × 8 pixels and lots of fun - StartHardware - Tutorials for Arduino