@misc{nikishkov_effect_on_1999, 
author={Nikishkov, G., Heerens, J., Hellmann, D.},
title={Effect on Crack Front Curvature and Side Grooving on CTOD Delta5 and J-integral in CT and 3PB-Specimens},
year={1999},
howpublished = {journal article},
note = {Nikishkov, G.; Heerens, J.; Hellmann, D.: Effect on Crack Front Curvature and Side Grooving on CTOD Delta5 and J-integral in CT and 3PB-Specimens. Journal of Testing and Evaluation. 1999. vol. 27, no. 5, 312-319.}}