1. ASCE. Report Card for America's Infrastructure. [cited 2010 Feb. 7], Available from: 〈http://www.asce.org/reportcard/2009/grades.cfm〉; 2009.
2. Recent trends in nondestructive inspections in state highway agencies;Rens;J Perform Constr Facil,1998
3. Ultrasonic tomography of grouted duct post-tensioned reinforced concrete bridge beams;Martin;NDTE Int,2001
4. Inspection of concrete using air-coupled ultrasonic pulse velocity;Cetrangolo;ACI Mater J,2010
5. Impact-Echo: the complete story;Sansalone;ACI Struct J,1997