Odom's 'CCENT/CCNA ICND1 Official Exam Certification Guide', page 145, under User Datagram Protocol, 2nd paragraph states "...VoIP uses UDP because...".
Lammle's 'CCENT Cisco Certified Entry Networking Technician Study Guide', page 81, last paragraph before it begins discussing UDP Segment Format says "So if you're using Voice over IP (VoIP), for example, you really don't want to use UDP, ..."
I suppose it really doesn't matter at this point, but that's a bit worrisome