I'm currently working on trying to obtain signatures from all former general managers of the Metropolitan Opera in New York.  I've made some decent headway but I wanted to try this forum since I'm pretty new to the game and I know that what I'm attempting is going to be difficult since the signatures I'm after are from men who aren't necessarily well known historical figures.  I've listed the names that I'm still looking for below.  Any help or suggestions on where I could look would be greatly appreciated. 

Henry E. Abbey, Edmund C. Stanton, John B. Schoeffel, Maurice Grau, Herbert Witherspoon, Goran Gentile, Anthony A. Bliss, Bruce Crawford, Hugh Southern.