When Father Michael is joking with Jessica about using a priest as the main character of one of her novels, he mentions the character of Father Dowling, created by Ralph McInerny. Of course, former cast member Tom Bosley went on to star in the series based on that character.
Seen on the chalkboard in Jessica's class is "Read Chapter 5-How It Works". This is a reference to the "Big Book" of Alcoholics Anonymous.