Lin, J.-T. (1993) Identification of photoreceptor locations in the compound eye of Coccinella septempunctata Linnaeus (Coleoptera, Coccinellidae).
Journal of Insect Physiology Volume 39, Issue 7, July 1993, Pages 555-562. doi:10.1016/0022-1910(93)90037-R
Land M.F. (1997)
Visual Acuity in Insects.
Annu. Rev. Entomol. 42:147-177
Warrant E.J., Nilsson D.-E. (1998) Absorption of White Light in Photoreceptors. Vision Res., Vol. 38, No. 2, pp. 195-207. PII: S0042-6989(97)00151-X
Stavenga D., Smits R.P., Hoenders B.J. (1993) Simple Exponential Functions Describing the Absorbance Bands of Visual Pigment Spectra. Vision Res. 33(8) pp. 1011-1017. doi:10.1016/0042-6989(93)90237-Q