Possessive forms of words ending in “s”
There seems to be great confusion about how to show possessive nouns that end with the letter “s.” The confusion is only increased when you find different grammar guides taking differing stances.
Which is correct?
Charles’s book…
Charles’ book…
In reality, both are. Consistency is the name of the game though. Make sure you stick with the same pattern throughout your writing.
You can find more excruciating details about this rule on this blog.