1. Classification of prepaid cards based on multivariate treatment of data obtained by X-ray fluorescence analysis 
Minemasa Hida, Toshiyuki Mitsui 
Forensic Science International 
Volume 119, Issue 3, Pages (July 2001)
DOI: /S (00)00459-X

2. Fig. 1 XRF spectrum of a real turnpike card. Mo tube, 45kV, 4μA.
Forensic Science International  , DOI: ( /S (00)00459-X)

3. Fig. 2
Relationship between Ti/Mo and Fe/Mo in 200 subway cards. (■): Group I; (□): Group II; (•): Group III; (○): Group IV; (▴): Group V; (▵): Group VI; (♦): Group VII.
Forensic Science International  , DOI: ( /S (00)00459-X)

4. Fig. 3
Relationship between Ti/Mo and Fe/Mo in 32 turnpike cards. (□): counterfeit I; (▵): counterfeit II; (♦): real I; (•): real II; (○): white card.
Forensic Science International  , DOI: ( /S (00)00459-X)

5. Fig. 4 Dendrogram of 200 subway cards. I–VII: Group I–VII.
Forensic Science International  , DOI: ( /S (00)00459-X)

6. Fig. 5
Relationship between 1st and 2nd PCS for 200 subway cards. (■): Group I; (□): Group II; (•): Group III; (○): Group IV; (▴): Group V; (▵): Group VI; (♦): Group VII.
Forensic Science International  , DOI: ( /S (00)00459-X)

7. Fig. 6
Relationship between 1st and 2nd PCS for 32 turnpike cards. (□): counterfeit I; (▵): counterfeit II; (♦): real I; (•): real II; (○): white card.
Forensic Science International  , DOI: ( /S (00)00459-X)