Some people will tell you that it’s fine to say “a friend of John” and that it’s also fine to say “John’s friend,” but “a friend of John’s” is another matter. “The double possessive is redundant and ...
A reader asks: How do we write the possessive form of names that end in s – for example, Davis's or Davis'? This is not only a long-standing area of disagreement and inconsistency among writing guides ...