Buy ThinkRobotics ArduPilot APM2.8 With M8N GPS Online – ThinkRobotics.com
UAV tutorials and Guides - UNMANNED TECH
Arducopter Quickstart Guides and Tips - Arduino based Arducopter UAV, the open source multi-rotor
Adding External Configuration GPRS Telemetry Module to APM 2.6 or Walkera X350 Pro - Blogs - diydrones
Raspberry Pi <-> APM 2.6 Communication and Control - ppt video online download
3dr Radio Telemetry 433mhz 433 1000mw Data Telemetry Ttl & Usb Port 2-3km Distance For Apm 2.6 2.8 Pixhawk Pixhack Rc Quadcopter - Parts & Accs - AliExpress
Archived:APM 2.5 and 2.6 Overview — Copter documentation