http://www.verisign.com/support/install/intermediate.html
For Verisign.com trial certificates go to:
http://www.verisign.com/support/verisign-intermediate-ca/Trial_Secure_Server_Root/index.html
For Trustcenter.de go to:
http://www.trustcenter.de/certservices/cacerts/en/en.htm#server
For Thawte.com go to:
http://www.thawte.com/certs/trustmap.html