1. Battye, R., Battye, W., Overcash, C. and Fudge, S. 1994.Development and Selection of Ammonia Emission Factors, 1–111. Research Triangle Park, NC: US Environmental Protection Agency. EPA Contract Number 68-D3-0034, Work Assignment 0–3;
2. Gay, S. W. and Knowlton, K. F. 2005.Ammonia Emissions and Animal Agriculture, 1–5. Blacksburg, VA: Virginia Cooperative Extension. Publication 442–110
3. The Adverse Effects of Ammonia on Chickens Including Resistance to Infection with Newcastle Disease Virus