I hate to be that guy, but point 5 under what not to do should not have an apostrophe for the word "gurus"
Edit: I got downvoted for this comment, but the author has made the change. My sacrifice was not in vain!
Edit: I got downvoted for this comment, but the author has made the change. My sacrifice was not in vain!
(If the word ends with an 's' you can (or not) add only an apostrophe and omit the added 's', afaik it's down to style/how you'd pronounce it. 'Socrates' work' for example, because 'Socrates's' looks and sounds awkward.)