I wonder what makes the comma before "among them ..." correct, assuming it is so? Does listing qualify for a comma? I would have thought of using a colon not a comma. What kind of phrase is after that comma? Absolute does not begin with a preposition. I wonder if there is any rule I could follow.
Professor Lerer elucidates a number of key linguistic concepts, among them Grimm's Law, the Great Vowel Shift that swept Britain between 1400 and 1600, and the stimulating intellectual theories of Noam Chomsky, the father of modern linguistics.
Source: History of the English Language by Seth Lerer