Infrared and Raman spectra of magnesium ammonium phosphate hexahydrate (struvite) and its isomorphous analogues. I. Spectra of protiated and partially deuterated magnesium potassium phosphate hexahydrate - V. Stefov, B. Šoptrajanov, F. Spirovski, I. Kuzmanovski, H. D. Lutz, B. Engelen (My University, 2004)