I need to consider if such a PDF is publicly available. Let me recall. Some university repositories might have papers on Croatian history. Or maybe the original title is in Croatian, and they're having trouble finding the English version. The name "Zmaj" means dragon in some European languages, and "orlovi" is eagles. The battle took place in 1590 in the village of Zmajevac near Kostajnica. The Habsburgs defeated the Ottomans there.