Griebel U., Peichl L. (2003)
Colour vision in aquatic mammals—facts and open questions.
Aquatic Mammals 29(1): 18-30
Meredith RW, Gatesy J, Emerling CA, York VM, Springer MS (2013)
Rod Monochromacy and the Coevolution of Cetacean Retinal Opsins.
PLoS Genet 9(4): e1003432. doi:10.1371/journal.pgen.1003432
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