HCD 1519 1 MHz reference oscillator

[FransW]

I am looking for information and manual of a HCD Research 1 MHz oscillator.
The internet does not contain any information on this equipment. Some foto's and
descriptions of people who own(ed) this oscillator but nothing else.
It is very old, I estimate over 40 - 50 years but mine is in good working condition.
The inner parts are an OCXO, a power supply, some regulating electronics and/or dividers (?).
Attached are 2 pictures.
If anyone can give me some more information I would be very thankfull.

Best regards,
Frans