I want to replace one latch.
Can You help me?
Thanks,
Lloyd

I'm afraid we have no such source. These haven't been made for the better part of a century so I don't think you're going to find an identical match anywhere unless you're very, very lucky. Your best bet is probably going to be a consumer-to-consumer marketplace like Facebook or eBay, but even that's a Hail Mary. You're essentially looking for a collector's item.
At the end of the day, you're probably going to have to put in the work to adapt modern parts to work on this window in their place.