Original Mac System Software

[glenesharp]

My wife's cousin is looking for some old operating system (400k) disks for the original Mac 128k.
The computer is in operating condition but he doesn't have the operating system to boot it up.
It requires a version of the operating system between Mac OS 0.97 through 3.3 (System 3.2 and Finder 5.3).
How is that for a blast from the past?
Let me know if you have any ideas on potential sources.

He also has an original Next computer as part of his collection of original versions of computers.
Thanks,
Glen