Complex sentence: In 1949, Perišin graduated from the University of Zagreb Faculty of Economics and has decided to continue his studies in Belgrade, defending his doctoral thesis at the University of Belgrade Faculty of Economics in 1959.
Split into simpler sentences: In 1949, Perišin graduated from the University of Zagreb Faculty of Economics. He continued studies at the University of Belgrade, and defended his doctoral thesis at the Belgrade Faculty of Economics in 1959.