https://hackaday.com/2016/07/01/wired-networking-for-the-esp8266/
https://github.com/esp8266/Arduino/issues/962
http://pic-microcontroller.com/esp8266-10-base-t-ethernet-driver/
https://www.youtube.com/watch?v=hKuZ6ZJeyNU
https://www.reddit.com/r/esp8266/comments/7l08qh/how_to_interface_esp8266_to_enc28j60_ethernet/
https://iot.stackexchange.com/questions/932/esp8266-with-ethernet-connection/941
https://hackaday.com/2016/04/01/ethernet-controller-discovered-in-the-esp8266/
https://www.youtube.com/watch?v=XKnyAYKP434
https://github.com/cnlohr/espthernet
http://www.esp8266.com/viewtopic.php?f=13&t=1184
https://www.reddit.com/r/esp8266/comments/5melmk/esp_ethernet_equivalent/
https://forum.mysensors.org/topic/5017/ethernet-gateaway-with-wemos-d1-esp8266/10
http://www.microchip.com/wwwproducts/en/en022889
https://www.bigtronica.com/comunicaciones/537-modulo-ethernet-enc28j60-5053212005375.html?search_query=ethernet&results=7