1. Nitrogen and Phosphorus Recovery from Human Urine;Antonini,2009
2. Bundes-Bodenschutz- und Altlastenverordnung 2004 §8 Abs.2
3. Human Faeces, Urine and Their Utilization;Chy,1978
4. Heavy Metals Entering Sewage - Treatment Works from Domestic Sources;Comber;CIWEM.,1996