I've been looking for information about a concert I went to at Winterland when I was a teenager.  It was the Mike Bloomfield, Paul Butterfield and Elvin Bishop.  I remember leaving the first night and thinking that I had just seen the best show.  I went back the next night an was blown away again.  Using your site I was able to find the dates which was February 23 & 24 1973.  I found the record of Paul Butterfield's set, but if anyone know where to find recording of Mike Bloomfield's set I would love to know.  Maybe the vault will release it!!