(1) ESP8266 official site:
http://espressif.com/zh-hans/
(2) Manual for Nodemcu：
https://github.com/nodemcu
API for NodeMCU:
https://github.com/nodemcu/nodemcu-firmware
(3) Lua：
http://www.lua.org/
http://baike.baidu.com/view/416116.htm
http://zh.wikipedia.org/wiki/Lua
(4) eLua:
http://www.eluaproject.net/
(5) LuaLoader
http://benlo.com/esp8266/index.html#LuaLoader
https://github.com/GeoNomad/LuaLoader