This may be somewhat of a side note to the question.

Personally I don't feel that the Church can or should enforce any sabbath laws in any way shape or form. The sabbath was not given to the Church. The sabbath was given to Adam (mankind) in the creation. Jesus also confirms this when he say's "the sabbath was made for man."
The commandment is to work 6 days and rest the 7th..thus keeping the sabbath (rest day) seperate (holy) from the other 6.

I suppose that if your normal 6 day work is buying books, then buying books on the sabbath would be breaking the sabbath. Or, if someones 6 day work week was selling books in the church book store, then doing so on the sabbath would be breaking the sabbath. But, a blanket statement or binding law that buying a book on Sunday is sin is pharisaical, imo.

__________________
Shawn
Orthodox Presbyterian
Denver, Colorado

Open my eyes Lord, that I may behold wondrous things out of your law. Psalm 119:18
http://reformedmoses.blogspot.com/