Atmospheric Response for MeV γ Rays Observed with Balloon-borne Detectors oleh Christopher M. Karwin, Carolyn Kierans, Albert Y. Shih, Israel Martinez Castellanos, Alex Lowell, Thomas Siegert, Jarred Roberts, Savitri Gallego, Adrien Laviron, Andreas Zoglauer, John A. Tomsick, Steven E. Boggs, for the COSI Collaboration