"[An] argument source to refer to materials whose claims a writer affirms, disputes, refines, or extends in some way. To invoke a common metaphor, argument sources are those with which writers enter into 'conversation.'"
Before you begin your search, it's important that you understand how a database figures out what you're looking for.
The databases below cover specific subjects. Select the database based on your topic. Look at the database descriptions to help you. For example, PsycINFO, which covers mental and behavioral health, would be good for articles about interventions or depression. Topics pertaining to education, try ERIC and topics about older adults, try AgeLine.