Helion have just published a new book on the Chaco War:
https://www.helion.co.uk/military-history-books/the-chaco-war-1932-1935-fighting-in-the-green-hell.php?sid=c1a23c5df689953d979f45f1fc5bb3d9
Taking advantage of the special launch offer price I ordered a copy which arrived today.
It is in the same large slim paperback format as their title on the Chaco air war (by the same authors). Filled with black and white photos (some of which are new to me) and with the centre pages filled with colour plates, it's not what you would call the definitive account of the ground war, but then you can turn to Farceau or English for a fuller account.
What struck me was the information on the trucks used; both colour plates and photos provide details which are often sketchy. There is at least one photo of a water truck and in another an ambulance.
If you are interested in the Chaco War, I'd wholeheartedly recommended buying a copy. With this and the companion volume on the air war; a copy of the Osprey and Adrian English's "Green Hell", you will have enough to game the conflict using Irregular Miniatures or Khurasan's figures in 15mm.
I also note the Amazon have a Kindle version (as well as paperback) of Estigarribia's memories in English translation:
https://www.amazon.co.uk/Epic-Chaco-Marshal-Estigarribias-1932-1935-ebook/dp/B07PBQRLHZ/ref=sr_1_10?crid=2TM89HRRYDN39&dchild=1&keywords=chaco+war&qid=1599310480&sprefix=Chaco+War%2Caps%2C186&sr=8-10