s://tools.ietf.org/html/rfc958 Mills, D. "Network Time Protocol Version 3: Specification, Implementation and Analysis." IETF, RFC 1305, 1992. https://tools.ietf.org/html/rfc1305 Mills, D. "Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI." IETF, RFC 4330, 2006. https://tools.ietf.org/html/rfc4330 Mills, D., J. Martin, J. Burbank, and W. Kasch. "Network Time Protocol Version 4: Protocol and Algorithms Specification." IETF, RFC 5905, 2010. https://tools.ietf.org/html/rfc5905 Mills, D. "Security Requirements of Time Protocols in Packet Switched Networks." IETF, RFC 7384, 2014. https://tools.ietf.org/html/rfc7384 Mills, D. "Computer Network Time Synchronization: the Network Time Protocol on Earth and in Space," Second Ed., CRC Press 2011 Mills, David "Network Synchronization Research Project." https://www.eecis.udel.edu/~mills/ntp.html Moreira, P., P. Alvarez, J. Serrano, I. Darwezeh, and T. Wlostowski. "Digital Dual Mixer Time Difference [DDMTD] for Sub-Nanosecond Time Synchronization in Ethernet." 2010 IEEE International Frequency Control Symposium, 2010. https://ieeexplore.ieee.org/document/5556289 SMPTE. "SMPTE Profile for Use of IEEE-1588 Precision Time Protocol in Professional Broadcast Applications." SMPTE ST 2059-2:2015, 2015. https://ieeexplore.ieee.org/document/7291608 UCA International Users Group (UCAlug). Precision Time Protocol Profile IEC 61850 Interoperability Testing (IOP), "IEC 61850 2019 Interoperability Testing (IOP) - Final Test Report." UCAlug, 2019. caiug.org/IOP_Registration/IOP%20Reports/IEC%2061850%202019%20IOP%20Final%20Report Chapter 8 IEEE Standards Association. "1588 Standard for Precision Synchronization Protocol for Networked Measurement and Control Systems." IEEE Std. 1588:2008, 2008. https://standards.ieee.org/standard/1588-2008.html IEEE Standards Association. "1588 Standard for Precision Synchronization Protocol for Networked Measurement and Control Systems." IEEE Std 1588:2019, 2019. https://standards.ieee.org/standard/1588-2019.html ITU-T. "Q13/15 - Network sy