instructables.com - Programming ESP8266 ESP-12E NodeMCU Using Arduino IDE

github - Arduino core for ESP8266 WiFi chip

geekstips-Communication between ESP8266 modules

arduino forum-Communication between two NodeMcu WIFI modules

github - ESP8266wifi library (may not be necessary, might be included in Arduino IDE??)

github - wifiUdp library

USB Serial port driver for ESP8266 NodeMCU V 0.9

ChiBots S&R project joystick specs

Current Arduino source for ESP8266 wifi remote S&R Romi robot