Teegarden, B. J., Watanabe, K., Jean, P., Knödlseder, J., Lonjou, V., Roques, J. P., et al. (2005). INTEGRAL SPI limits on electron-positron annihilation radiation from the galactic plane. The Astrophysical Journal, 621(1), 296-300. doi:10.1086/426859.