Ernährung des Hundes: Grundlagen - Fütterung - Diätetik ; 146 Tabellen - Helmut Meyer, Jürgen Zentek - Google Books
Factorial calculation of calcium and phosphorus requirements of growing dogs | PLOS ONE
Calcium & Phosphorus - Why are they so important? What do they secure? Guidance values? - Herrmann's Manufaktur - Hundefutter & Katzenfutter in Bio-Qualität