Consider a person whose name is "Lehman".
In the sentence
"I read Lehman's documents."
why is it "Lehman's" and not "Lehmans' " ?
closed as general reference by Andrew Leach♦, Cerberus, Hellion, cornbread ninja 麵包忍者, Kristina Lopez May 30 '13 at 22:10
This question is too basic; it can be definitively and permanently answered by a single link to a standard internet reference source designed specifically to find that type of information. If this question can be reworded to fit the rules in the help center, please edit the question.
The usual rule applies here - just add
Perhaps you're confused by the fact that it's documents rather than document? It's still Lehman's in both cases. It would be Lehmans' if there were two people called Lehman and the documents belonged to both of them.