Are these correct usage?
The car was Hank Williams's.
There are three Hank Williams living in that town.
The car was the Williams'.
Many people have trouble with apostrophes. There are several rules, depending on the form of the noun and its function. Here are a couple of links:
http://owl.english.purdue.edu/handouts/grammar/g_apost.html
http://en.wikipedia.org/wiki/Apostrophe
As you'll see, there's some flexibility when it comes to adding an additional "s" after the apostrophe in a name that ends in "s." Here's a quote from the wikipedia link:
"In general, a good practice is to follow whichever spoken form is judged better:
the boss's shoes,
Mrs Jones' hat (or
Mrs Jones's hat, if that spoken form is preferred). In many cases, both spoken and written forms differ between writers."
To take your questions individually:
"The car was Hank Williams's" is correct, but it's kind of awkward. A smoother way to write it would be "The car belonged to Hank Williams."
"There are three Hank Williams living in that town" is incorrect. It should be "There are three Hank Williamses living in that town," but that's also awkward. A better way to write it would be something like "There are three people named Hank Williams living in that town."
"The car was the Williams'." is not correct. It should be "The car was the Williamses'."
[
Note on 12-5-08. I have corrected some of what I wrote above based on the astute observations, below, by Chase and IceCreamExpress.]
