Fugger's role in Tetzel's indulgences

Oct 2012
In his book on Fugger, Greg Steinmetz tells a version that has Jacob Fugger as the instigator of Tetzel's indulgences, as a way to help Albrecht of Mainz repay a big loan Fugger extended him. Unfortunately, Steinmetz is a little short of footnotes. Can anyone point to original or scholarly secondary sources that tells this story?