In the latest ASTM Standard Guide for GSR analysis by Scanning Electron Microscopy/Energy Dispersive X-ray spectrometry (SEM-EDX) particles containing lead, antimony and barium, and respecting some rules related to the morphology and to the presence of other elements are considered characteristic of GSR. The most definitive method to determine whether a particle is characteristic of or consistent with GSR is by its elemental profile. An approach to the identification of particles characteristic of or consistent with GSR is to compare the elemental profile of the recovered particulate with that collected from case-specific known source items, such as the recovered weapon, Cartridge cases or victim-related items whenever necessary. This approach was called ‘‘case by case’’ by Romolo and Margot in an article published in 2001. In 2010 Dalby et al. published the latest review on the subject and concluded that the adoption of a "case by case" approach to GSR analysis must be seen as preferable, in agreement with Romolo and Margot.