Best SNG book x2

I decided to buy a pokerbook to learn more about SNG's. I mainly play SNG, I prefer 9man SNG and sometimes play MTT (I never play cashgame).

I've done some research and most people online recommend " Sit 'n' Go Strategy - Collin Moshman" (from what I could find).
For me to not have to pay delivery fee on the site I'm ordering, I should buy another book, which I have no problem with .

Any recommendations?

I was thinking "Kill Everyone by Lee Nelson" or "Heads-Up No-Limit Hold 'em - Collin Moshman".
Which one should I get as second or do you have any other recommendations?

How to study poker by Sky Matsuhashi this will help you learn to improve your game and get the most out of any other book.