New to this , Best authenticator for coas?

[JoGirl]

HI all, glad to have found this forum.

I am just getting into collecting as well as trading/selling baseball items. A friend has literally gifted me thousands of cards and baseball items. I have been a nascar collector for decades, as well as some other industries, but baseball is a new frontier for me.

I have not gone through everything yet as it is going to take a long time. I do have one item that's a signed joe dimaggio jersey with some of his cards (unsigned) that I think may be pretty valuable. I am wondering who you guys feel is the best and respected authenticator of baseball autographs? This one has a COA from about 11 years ago from William Tell REsearch.

Is it necessary to get it re-authenticated for the purposes of grade/condition since so much time has passed? At the time it was given a 9.5.

I'd like to know so that as I come across cards and other items I know where to go and who to trust.

Thanks everyone - Jo