Abdo, A. A., Ackermann, M., Ajello, M., Atwood, W. B., Axelsson, M., Baldini, L., et al. (2009). Fermi large area telescope gamma-ray detection of the radio galaxy M87. The Astrophysical Journal, 707(1), 55-60. doi:10.1088/0004-637X/707/1/55.