The ATP platform test, the →D⇋ATP test and the direct microscopic count procedure as methods of estimating the microbial quality of raw milk / L.P.M. Langeveld and C.B. van der WaalsDetermination of calf rennet in cheese / J. Stadhouders, G. Hup, and C. B. van der WaalsInactivation of native milk proteinase by heat treatment / F. M. Driessen and C. B. van der Waals