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2. Langley A. 2013. Enhancing digital certificate security. Google Online Security Blog; http://googleonlinesecurity.blogspot.de/2013/01/enhancing-digital-certificate-security.html. Langley A. 2013. Enhancing digital certificate security. Google Online Security Blog; http://googleonlinesecurity.blogspot.de/2013/01/enhancing-digital-certificate-security.html.
3. Langley A. 2013. Further improving digital certificate security. Google Online Security Blog; http://googleonlinesecurity.blogspot.co.uk/2013/12/further-improving-digital-certificate.html. Langley A. 2013. Further improving digital certificate security. Google Online Security Blog; http://googleonlinesecurity.blogspot.co.uk/2013/12/further-improving-digital-certificate.html.
4. Laurie B. 2011. Improving SSL certificate security. Google Online Security Blog; http://googleonlinesecurity.blogspot.co.uk/2011/04/improving-ssl-certificate-security.html. Laurie B. 2011. Improving SSL certificate security. Google Online Security Blog; http://googleonlinesecurity.blogspot.co.uk/2011/04/improving-ssl-certificate-security.html.