and
Atkins' is just the possessive form of Atkins.
[link|http://www.fortunecity.com/bally/durrus/153/gramch17.html|In American English], singular nouns ending in s can also indicate possession by means of a final apostrophe.Or, are you getting into "smart quotes"?
e.g. James' scarf
Dickens' novels
In these examples, a final apostrophe is used with the singular proper nouns James and Dickens to indicate possession.