1. Impact-echo;Sansalone,1997
2. Detecting voids in grouted tendon ducts of post tensioned concrete structures using the impact-echo method;Jaeger;ACI Struct J,1996
3. Impact-echo: the complete story;Sansalone;ACI Struct J,1997
4. Stack imaging of spectral amplitudes based on impact-echo for flaw detection;Ohtsu;NDT&E Int,2000
5. SIBIE procedure for identification of ungrouted post-tensioning duct in concrete;Alver;Fract Mech Concr Concr Struct,2007