1. American Angus Association 2014. Angus genetic trend by birth year. www.angus.org/nce/genetictrends.aspx. (Accessed 1 October 2014.)
2. American Gelbvieh Association 2014. Genetic trend. http://www.gelbvieh.org/education/siresummary.html. (Accessed 1 October 2014.)
3. Pan American Hereford cattle evaluation;American Hereford Association;Genetic trend.,2014
4. American International Charolais Association 2014. Charolais national cattle evaluation. http://www.charolaisusa.com/epdstats.html. (Accessed 1 October 2014.)
5. American Simmental Association 2014. https://herdbook.org/simmapp/template/trends,TrendIndex.vm. (Accessed 1 October 2014.)