“I always suspected a link between Shell and Dilbert…. C23 (Carel van Bylandtlaan 23) is one of the Shell central office buildings in the Hague”
http://www.unitedmedia.com/comics/dilbert/
This website and sisters royaldutchshellgroup.com, shellnazihistory.com, royaldutchshell.website, johndonovan.website, and shellnews.net, are owned by John Donovan. There is also a Wikipedia segment.