@misc{Hagen_A._The_1980,
 author={Hagen, A. and Stenseth, N. C. and Ostbye, E. and Skar, H. J.},
 volume={25},
 number={4},
 copyright={Rights Reserved - Free Access},
 journal={Acta Theriologica},
 address={Białowieża},
 howpublished={online},
 year={1980},
 language={eng ; sum. eng. ; pol.},
 title={The eye lens as an age indicator in the root vole},
 type={Text},
 URL={http://rcin.org.pl/ibs/Content/10683/PDF/BI002_2613_Cz-40-2_Acta-T25-nr4-39-50_o.pdf},
 keywords={age indicator, eye lens, Microtus oeconomus, soczewka oka, ocena wieku, gryzonie, Nornik północny},
}