The information for this podcast came primarily from two books:
Bombing Hitler, by Helmut Haasis
Bombing Hitler: The Story of the Man Who Almost Assassinated the FührerThe Lone Assassin, by Helmut Ortner
Lone Assassin: The Epic True Story of the Man Who Almost Killed HitlerGeorg Elser was interrogated many times by the Nazi government. These interrogations were preserved which is why much of what he did is public knowledge and discussed in these books in detail.