Amazing resource. The original book had 500k references, and this version claims to add 100k more. After buying a a physical copy of the Thompson chain reference bible (which has about 100k references) I got the idea to search for it here in digital format. Logos was selling it, but currently doesn't have the rights to sell it and removed it, and so I searched and found the NTSK instead. Well, I'm glad the Thompson wasn't for sale when I was searching because this resource is FAR more exhaustive with a lower price tag. Get this resource it's an amazing system, especially if you get tired of flipping pages back and forth on the Thompson chain reference.