Estupigan, R. (1999). What's your driving attitude? Manila Bulletin.
Chicago-viite (17. p.)Estupigan, Ruth. "What's Your Driving Attitude?" Manila Bulletin 1999.
MLA-viite (9. p.)Estupigan, Ruth. "What's Your Driving Attitude?" Manila Bulletin, 1999.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.