Theodosios Tsiakis and George Stephanides and George Pekos, Considerations of Public Key Infrastructure (PKI), Functioning as a Chain of Trust in Electronic Payments Systems. journal = {International Journal of Computer and Information Engineering}, [online]. World Academy of Science, Engineering and Technology. September 2008, vol. 21(9). 3274 - 3281 [viewed 23 September 2024]. Available from: https://publications.waset.org/pdf/15212.