05-14-2018 08:09 AM
05-14-2018 11:54 AM - edited 05-14-2018 11:55 AM
You may find this article quite helpful, if you haven't already seen it:
Why not post some photos here, to give people an idea of what you've got? We can't value them, but we can give you our thoughts, and maybe point you in the right direction.
05-14-2018 12:03 PM
Nate Sanders and Steve Raab would both be interested. So would Heritage, Cowan's, Christie's and Sotheby's, for that matter. You can find contact information on them all with a Google search.
Be prepared to provide information regarding provenance, in particular.
Or, as argon suggested, post a few pictures here of the entire signature and the entire item it's on, and we may be able to give you a bit of help.