[1] RFC 2783 - Pulse-Per-Second API for UNIX-like Operating Systems, Version 1.0, 2021-04-11T13:49:49.000Z, 2021-04-12T08:41:36.180Z https://tools.ietf.org/html/rfc2783

[2] Available implementations of Pulse Per Second (PPS) API, 2021-04-12T08:42:30.000Z http://www.ntp.org/ppsapi/PPSImpList.html