H. Suhr, Wehnert, G., Schneider, K., Bittner, C., Scholz, T., Geißler, P., Jähne, B., and Scheper, T.,
“In-situ microscopy for on-line characterization of cell-populations in bioreactors, including concentration measurements by depth from focus”,
Biotechnology and Bioengineering, vol. 47, p. 106--116, 1995.
]