Detail of: After Padovanino, Cornelia and Her Sons, 17th century. Oil on canvas (142.5 x
118.1 cm). National Gallery, London: acquisition number NG70. Source: National Gallery.

Summon is usually the best starting point for finding articles, books and dissertations. 

• video intro to Summon (4 mins) 
• collection of guides if you need help with particular Summon searches

You may also want to run supplementary searches in these databases:

•  EBSCO: includes Business Source Premier
• Google Scholar: an alternative to Summon
  • info about using Scholar
  • video intro to Scholar (3 mins)
  • try also Google Dataset Search for economics statistics
• NexisUni