This autograph represents an extended period of mischievousness on my part. I did not expect to receive anything back.
I am the sole owner of this, and thus I have no LOA/COA, although the only reasonable explanation of a forgery would be that MT was using a proxy to answer her mail.
So have a look at a crossection of my callow youth.
As long as it's live ink it's authentic, IMO. Mother Teresa was a good signer as long as it's not a preprint or stamp.
It's most certainly pen. You can see it leak through on the dot at the end.
Sounds like you have the real deal. Congratulations!
Looks rather Divine to me!