Here are some keywords and phrases that may be useful in your searches. There may be additional terms that are useful--when you find a relevant article, examine the record for additional terms you might be able to try.
Value Added Resellers
Dell AND (sales OR marketing OR market strategy OR trends)
Results from the search above must use the term Dell and ANY ONE of the terms in the parentheses connected with OR.
Are some types of articles more reliable than others?