D. Otten, and H. F. A. Van den Weghe. “Nitrogen and Phosphorus Management on Pig Farms in Northwest Germany – Nutrient Balances and Challenges for Better Sustainability”. African Journal of Pig Farming 1, no. 1 (October 26, 2013): 1–10. Accessed August 5, 2025. https://elixirpublishers.in/index.php/ajpf/article/view/611.