Klein A., Brittain C., Hendrix S. D., Thorp R., Williams N., Kremen C. (2012) Wild pollination services to California almond rely on semi-natural habitatJournal of Applied Ecology 49 (3): 723732. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2664.2012.02144.x/abstract