Create a Joystick Using the Arduino Joystick Library 2.0 : 12 Steps (with Pictures) - Instructables
Programming Ponderings: Arduino Joystick Library
Using the joystick with Arduino
GitHub - malisipi/joystick_5pin: A joystick library for Arduino
GitHub - MHeironimus/ArduinoJoystickLibrary: An Arduino library that adds one or more joysticks to the list of HID devices an Arduino Leonardo or Arduino Micro can support.