Complex sentence: The question whether (and if so, to what extent) Marić contributed to Einstein's early work, and to the "Annus Mirabilis Papers" in particular, is controversial, however, the overwelming consensus among professional historians of physics is that she did not.
Split into simpler sentences: The question whether (and if so, to what extent) Marić contributed to Einstein's early work, and to the "Annus Mirabilis Papers" in particular, is controversial. However, the overwelming consensus among professional historians of physics is that she did not.