Boy, that's an understatement.  As best I can tell, the Rand UNIX( ??Bruce Borden??)  had them first, then they were in the UofI NCP (Steve Holmgren) and migrated to several places like MIT's ChaosNet, long before the BSD implementation.   BSD got them from the BBN TCP, which I think came from MIT's flavor. Still, it might have been from any of the other versions that were around at the time - I must have had a couple of different versions in different kernel sources for different V6 kernel hacks in those days, and I did not write any of them. If you look at the old USENIX tapes, you will likely see a couple of versions.

Clem