Boettcher, M., Schmidt, S., Latz, A., Jaeger, M. S., Stuke, M., & Duschl, C. (2011). Filtration at the microfluidic level: Enrichment of nanoparticles by tunable filters. Journal of Physics-Condensed Matter, 23(32): 324101. doi:10.1088/0953-8984/23/32/32410.