Lunde, K., Trimble, J. L., Guichard, A., Guss, K. A., Nauber, U., & Bier, E. (2003). Activation of the knirps locus links patterning to morphogenesis of the second wing vein in Drosophila. Development, 130(2), 235-248. Retrieved from http://dev.biologists.org/content/130/2/235.full.pdf+html.