@misc{heerens_development_of_2002, 
author={Heerens, J., Hellmann, D.},
title={Development of the Euro Fracture Toughness Dataset},
year={2002},
howpublished = {GKSS report},
note = {Heerens, J.; Hellmann, D.: Development of the Euro Fracture Toughness Dataset. Engineering Fracture Mechanics. 2002. vol. 69, 421-449.}}