Koyama S., Kino M., Giroletti M., Doi A., Giovannini G., Orienti M., Hada K., Ros E., Niinuma K., Nagai H. et al..  2016.  Discovery of off-axis jet structure of TeV blazar Mrk 501 with mm-VLBI. \aap. 586:A113.

Abramowski A., Acero F., Aharonian F., Akhperjanian A.G, Anton G., Balzer A., Barnacka A., U. de Almeida B, Becherini Y., Becker J. et al..  2012.  The 2010 Very High Energy $\gamma$-Ray Flare and 10 Years of Multi-wavelength Observations of M 87}. The Astrophysical Journal. 746:151.