References

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2.Nixon, Marion. “Beak and radula growth in Octopus vulgaris.” Journal of Zoology 170.4 (1973): 451-462.
3.Ikica, Zdravko, et al. “Analysis of beak morphometry of the horned octopus Eledone cirrhosa, Lamarck 1798 (Cephalopoda: Octopoda), in the south-eastern Adriatic Sea.” Acta Adriatica 55.1 (2014): 43-56.