A sample extract:

THE APOSTROPHE

5.2 Unusual Plurals

As a general rule, we never use an apostrophe in writing plural forms. (A plural form is one that denotes more than one of something.) Hence the things that those shops are selling are pizzas, videos, fine wines, cream teas, and mountain bikes. It is absolutely wrong to write pizza's,video's, fine wine's, cream tea's, and mountain bike's if you merely want to talk about more than one pizza or video or whatever. The same goes even when you want to pluralize a proper name:

She's trying to keep up with the Joneses.

There are four Steves and three Julies in my class.

Several of the Eleanor Crosses are still standing today.

Do not write things like Jones's, Steve's, Julie's or Eleanor Cross's if you are merely talking about more than one person or thing with that name.