I had seen a footnote in Socinco on Pesachim (Or, for a real reference see note on בדיתא לבאי in M.K. 11a), I do not currently remember which page but it referenced a city that was mentioned in the Gemara which the particular manDeamar had as part of his name because he was from there i.e. somewhere in bavel. The footnote said to reference page x in a book called ‘Obermeyer’ I didn’t know what that was so I tried to look it up. I found a guy by the name of Jacob Obermeyer whose life mission was partially to go to these obscure places and recreate Talmudic maps. The book had the name “Die Landschaft Babylonien im Zeitalter des Talmuds und des Gaonats: : Geographie und Geschichte nach talmudischen, arabischen und andern Quellen,, von Jacob Obermeyer; mit zwei Landkarten”
However, I could not seem to find any remanance of this book anywhere. Not for sale, nor pdf or hebrewbooks etc. And so does anybody know the whereabouts of such a book?