Barna, G. (1990). The frog in the kettle: What Christians need to know about life in the year 2000. Regal Books.
Chicago-viite (17. p.)Barna, George. The Frog in the Kettle: What Christians Need to Know About Life in the Year 2000. Ventura, Calif., U.S.A.: Regal Books, 1990.
MLA-viite (9. p.)Barna, George. The Frog in the Kettle: What Christians Need to Know About Life in the Year 2000. Regal Books, 1990.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.