War on the Equator bibliography?

[Hugmenot]

My Google limited skillz unrevealed only three:

1. Bryce Wood, The United States and Latin American Wars 1932-1942. New York, Columbia University, 1966.
2. David H. Zook, Jr., Zarumilla-Marañon: The Ecuador-Peru Dispute, New York, Bookman Associates, 1964.
3. Adrian J English, Maranon-Zarumilla: The Peru-Ecuador War of 1941

I expect there are more but I will leave that search to someone with more skillz than I have.