The information in the ABBbase comes from a large variety of sources, mostly tape lists from private collections.
First, I would like to especially acknowledge John Johnston for providing the lion's share of information. John has done years of work researching and building up a database of shows and setlists which he freely offered to Hittin' the Web. John's definitely one of the HTW Heroes!
Next, I would like to thank Kirk West who despite a nearly constant flow of questions and visits from fans still manages to respond as enthusiastically as he did to the first one! Kirk, you're an inspiration bro'!