Kodric, M., Riffeser, A., Seitz, S., Snigula, J., Hopp, U., Lee, C.-H., et al. (2015). The M31 near-infrared period-luminosity relation and its non-linearity for δ Cep variables with 0.5 ≤ log (P) ≤ 1.7. The Astrophysical Journal, 799(2): 144. doi:10.1088/0004-637X/799/2/144.