1. Guidelines for uniform beef improvement programs;Beef Improvement Federation,2002
2. Beef improvement federation certification criteria;Wilson,1993
3. Ultrasound Guidelines Council: The beef cattle ultrasound technician annual proficiency and certification program: certification procedures and policy (website): http://www.aptcbeef.org/Portals/aptcbeef/Documents/UGC%20Certifcation%20Guidelines.pdf. Accessed October 1, 2006.
4. Ultrasonic prediction of quality grade and percent retail cuts in beef cattle;Perkins;J Anim Sci,1997
5. Perkins T, Meadows A, Hays B: Study guide for the ultrasonic evaluation of beef cattle for carcass merit. Ultrasound Guidelines Council Study Guide Sub-Committee (website): http://www.aptcbeef.org/Portals/aptcbeef/Documents/UGC%20STUDY%20GUIDE.pdf. Accessed October 1, 2006.