Dearborn heaters

Does anyone know of a good source of information about Dearborn gas heaters? I have a couple of them and use them for backup in case my central heat goes out or the electricity goes off.
Also, does anyone know if heaters like these are still manufactured by anyone? The clsoest I've seen is the built-in heater in my second bathroom-it's the same type with the ceramic radiants and all, but the house is 15-20 years old and I can't find any manufacturer's mark, label, sticker or anything on it.

Thanx...