The roots of the religion and how it started is pretty cult-like...making predictions of what exact day Jesus will arrive, also the same thinking like Mormons have, the SDA think they are the only right religion and that everything else is wrong.
As the husband of a former SDA member I can tell you that the greatest resource you can find is someone who has left the denomination.
There is plenty of information in print that they produce about their own beliefs, but most does not approach the level of heresy that goes on in person during sermons and bible studies.
If you really want the worst of the worst in print you have to get a hold of some of their various theological magazines not the main stream stuff that they hand out, I am talking about the magazines that they only send to other Adventists, most of which is Ellen White veneration. Also, the two main teachers/theologians today are Doug Bachelor and Mark Finley both of whom produce countless articles, videos, and audio tapes.
You are welcome. The Christian Apologetics Research Ministry (CARM) also has excellent material on Seventh-Day Adventism. The owner of the website however doesn't promote a Reformed view of the Lord's Day. So exercise caution on this matter. Click Seventh Day Adventism | Christian Apologetics & Research Ministry.
The Faith Presbyterian Church Reformed of Mesquite has an article written by Dr. Richard Bacon which provides a Reformed response to the SDA insistence on Saturday public worship. The church's website has a policy regarding linking to its materials, and I'm not sure how that applies in a discussion forum. So just look for the article in the website. It's entitled "An Email Exchange With A SDA" and is found in the page "Onsite Articles."
A book (by Presbyterian and Reformed Publishing) that discusses Adventism is,
I bought this book half a year ago, but haven't read it yet.
I got acquainted with Seventh-Day Adventism initially through a US-based netwok called 3 Angels Broadcasting Network whose programs were still being aired in my country until quite recently. I had no knowledge of Calvinism when I started watching its shows, and I thought the network was owned by some evangelical organization. Many of the programs discuss Adventist doctrine.