Ralph Kimball, "The 38 Subsystems Of ETL"
[http://www.intelligententerprise.com/showArticle.jhtml;jsessionid=O02BH0CP4TINCQSNDBGCKH0CJUMEKJVN?articleID=54200319]
: "The extract-transform-load (ETL)
system, or more informally, the "back room," is often estimated to consume 70
percent of the time and effort of building a data warehouse. But