$1.$ Classify each of the following sources of information as either primary or secondary tax research authority:

a$.$ An article in the AICPA$$s journal, The Tax Adviser

b$.$ A discussion of recent federal tax legislation in the Checkpoint Edge Tax Coordinator $2$d Tax Service

c$.$ A U$.$S$.$ Supreme Court decision on a tax issue

d$.$ The Income Tax Treaty between the U$.$S$.$ and India

e$.$ The National Association of Tax Professionals TaxPro Weekly Newsletters