I was practicing with an article from DW.de and the following sentence appeared peculiar to me:
Der Wald machte den Menschen damals aber auch aus anderen Gründen Angst, so Professor Albrecht Lehmann.
I looked at the dictionary but wasn't able to find a satisfactory explanation for "so" in this case.
What does "so" mean exactly here? Or is there some sort of omission in the sentence?