Kohnle, A., Horns, D., & Krawczynski, H. (2001). Observations of Mkn 421 and Mkn 501 in 2000 and 2001 with the HEGRA stereoscopic system. In M. Simon, E. Lorenz, & M. Pohl (Eds.), 27th International Cosmic Ray Conference (pp. 2605-2608). Copernicus Gesellschaft.