Disconnection detection through handshakes - @uskiara
BlueTooth Client Polling Rate Explained - @ewpatton
Links to bluetooth guides on communication, numeric data and arduino (dead link)
BLE Connection Starter Guide - @ewpatton
FAQ Section: BlueTooth/BLE and Arduino Starter
FAQ Section: BlueTooth/BLE and Micro:bit
FAQ Section: BlueTooth/BLE and HM-10
FAQ Section: BlueTooth/BLE nb158 and later (current release info)