addendum - letters from the Rebbe Rayatz נ"ע to RYDS
Here's what I have so far. There are more, I just can't post them all. Smaller pictures can be clicked on. I bring a page from Rakeffet's book as well, since one of you asked for "proof." I believe it was Elchonon. Not all of the letters are proof, but they're very nice to see in any case.