TY - RPRT TI - Fracture toughness data for brittle materials AU - Munro, R G AU - Freiman, S W AU - Baker, T L PY - 1998 PB - National Institute of Standards and Technology CY - Gaithersburg, MD SN - NIST IR 6153 DO - 10.6028/NIST.IR.6153 ER -