Catholic Encyclopedia article regarding prescriptions concerning the sabbath, its importance in the New Testament, and its origin.

Contains information about who made the sabbath and why, which day should be observed, and the importance of keeping the sabbath holy.

This site, dedicated to the sabbath, publishes numerous articles and sermons about what the subject and when it should be observed.

Provides a bible study on the topic, including a list of the words searched for, lists of texts found as well as lengthy commentary, and conclusions which can be drawn.