1. Light signals perceived by crop and weed plants;Ballaré;Field Crops Res.,2000
2. Bates D., 2013. Package ‘lme4’–Linear mixed-effects models using S4 classes. http://cran.r-project.org/web/packages/lme4/lme4.pdf (accessed 30.07.13).
3. Behm, C., 2012. Grünland-Erhaltungsverordnungen wirken. http://www.vhoe.de/fileadmin/PDF/Biodiversitaet/2012-11-30_PM_Entwicklung_beim_Gruenland_2012_pdf (accessed 29.03.14).
4. Photosynthesis light sensor and meter;Biggs;Ecology,1971
5. BMU, BMELV, 2010. National Biomass Action Plan for Germany. Berlin. http://www.bmelv.de/SharedDocs/Downloads/EN/Publications/BiomassActionPlan.pdf?__blob=publicationFile (accessed 09.12.13).