http://report.saltcpa.com/2015/08/alabama-certificate-of-exemption-requirements-for-government-entity-projects-stc-1/#.VcuOQ_n763w
http://revenue.alabama.gov/salestax/Contractor_Notice_20140121.pdf
http://revenue.alabama.gov/salestax/whatsnew.cfm
http://revenue.alabama.gov/salestax/ST-EXC-01.pdf