1. Natuphos71, BASF, Mt. Olive, NJ.
2. Effectiveness of Natuphos phytase in improving the bioavailabilities of phosphorus and other nutrients for layers;van der Klis,1996
3. Improvement of phosphorus availability by microbial phytase in poultry and pigs;Simons,1992
4. Response of first cycle laying hens to supplemental phytase;Gordon,1996
5. Ross Breeders, Huntsville, AL.