1. The accuracy of colony counts in homogeneous liquid samples;Beckers;De Ware(n)-Chemicus,1979
2. Improved medium for sporulation of Clostridium perfringens;Duncan;Appl. Microbiol.,1968
3. Laboratory evaluation and certification;Forney,1978
4. Review of the centers of disease control proficiency testing programme in bacteriology;Griffin;Arch. Lebensmittelhyg.,1982