1. U.S. Geological Survey. IRON ORE
https://s3-us-west-2.amazonaws.com/prd-wret/assets/palladium/production/mineral-pubs/iron-ore/mcs-2017-feore.pdf
2. U.S. Geological Survey. LEAD
https://s3-us-west-2.amazonaws.com/prd-wret/assets/palladium/production/mineral-pubs/lead/mcs-2017-lead.pdf
3. U.S. Geological Survey. ZINC
https://prd-wret.s3-us-west-2.amazonaws.com/assets/palladium/production/atoms/files/mcs-2017-zinc.pdf
4. Labour Market Research and Analysis Branch. Industry Outlook Mining;Poult. Sci.,2014
5. Skills Shortage Report
https://www.bankwest.com.au/about-us/media-centre/news?redirurl=/media-centre/financial-indicator-series/bankwest-skill-shortage-report-2012-1292487426050