If you want to find the source of most retail products, all you have to do is purchase one. Usually there will be some sort of label that will give you either the manufacturers name or who is distributing it. In the case of large items, like mirrors, look on the back or the box it came in.
This will not help you much if the product is distributed by the retailer who is selling it.
Another way is to try the Internet, as you obviously have started doing.
Good luck in your quest,
John