RFC675 TCP/IP first specification: https://tools.ietf.org/html/RFC675

RFC793 TCP v4: https://tools.ietf.org/html/RFC793

TCP Wiki: https://en.wikipedia.org/wiki/Transmission_Control_Protocol

The TCP/IP guide at: http://www.tcpipguide.com/

Ask Wireshark for all Wireshark-related queries at: https://ask.wireshark.org/

Display filter references for TCP at: https://www.wireshark.org/docs/dfref/t/tcp.html

TCP analyze sequence numbers at: https://wiki.wireshark.org/TCP_Analyze_Sequence_Numbers

Helpful clips at: https://goo.gl/lVaEc9