Check out this great interview on Billy Goat history with Bill Sianis:
http://chicago.eater.com/archives/2013/04/17/billy-goat.php
For the complete history of the legendary Billy Goat Tavern, check out Rick Kogan’s Book “A Chicago Tavern” https://www.billygoattavern.com/souvenirs/index.php/books/book-a-chicago-tavern.html