The Society often fails to properly cite quotations for several reasons:
They feel that their word should be sufficient to establish the validity of the quote.
They don't want anyone to check up on them.
They want to save precious print space and so avoid putting in 'unnecessary' material.
The Society got badly burned with the 1985 Creation book. Although a couple of older books (Is the Bible Really the Word of God? 1969; Did Man Get Here By Evolution Or By Creation? 1967) contained a fairly complete bibliography, no one seems to have published an analysis of the quotations. When I was in college in 1979 I wanted to use some of the references for a paper defending the historicity of Noah's Flood, and creation over evolution. I found the references useless because they were often misrepresentations, or otherwise didn't support the writer's claim. Within seven years of the publication of the 1985 Creation book, discussions of its misrepresentations were appearing on several Usenet discussion groups, including talk.origins. I'm sure that over the years the Society got a huge number of letters taking them to task for their idiotic misrepresentations. I wrote 4-5 letters about it but never got a reply. Anyone who is interested in my extensive debunking of the book can find it here http://www.geocities.com/osarsif/index2.htm under the title "The WTS View of Creation and Evolution".
I have not yet tried to do an analysis of the 1998 Creator book, but it's pretty obvious that the Society uses quotations from many people involved in the self-styled "Intelligent Design Movement". Some of the references are fairly complete, but others are in the usual atrocious "one person said" style. If anyone wants to do some research, the Italian version of the Creator book will be somewhat more useful. By Italian law it supposedly must contain complete citations for all quoted material, so this is more useful than the English version. This also shows that, if they really wanted to, they could put complete citations in all of their literature. Unfortunately the Italian version still gives incomplete citatations in many instances. Also, the Society supposedly will supply complete references if requested, but I have not tried this.