Where can I get information on discontinued PZM microphones?

I recently came into possession of some old Crown mics. One is a PZM-30GP, quite
old, with the PX-T transformer. The other is a lavalier boundary mic that has a
PA-18 preamp. Could you email me any technical documentation on these mics?
Tom Van Meter

Reply: Here is a link to the Discontinued PZMs document.