Joachain, CJ., & Potvliege, RM. (1988). Differential Cross-sections for Positron Atomic-hydrogen Inelastic-scattering At Intermediate Energies. Physical review. A, Atomic, molecular, and optical physics, 38(8), 4337-4339. https://doi.org/10.1103/PhysRevA.38.4337 (Original work published 1988)