Discontinued - you can grab Adafruit Grand Central M4 Express featuring the SAMD51 instead!
Arduino Mega 2560 R3 (Atmega2560 - assembled)
Introduction to Arduino Mega 2560 - The Engineering Projects
Arduino Mega 2560 ATmega2560 MCU Rev3 Best Price
Arduino Mega - Electronics Infra
Arduino Mega 2560 R3 (Rev3): Review the Specs
Arduino Mega 2560 R3
Arduino Mega 2560 REV3 [A000067] : Electronics
A Comparison of Popular Arduino Boards, Arduino
ARDUINO MEGA Modern Electronics
Arduino Mega vs. Uno: Which One Should You Use?
Arduino Mega 2560 Pinout
INTRODUCTION TO Arduino mega 2560