Here are publications about GST by Mark Keating:
Practictioner’s Viewpoint – Calculating GST adjustments
Practitioner’s viewpoint – GST reform – practical implications and problems
Practitioner’s Viewpoint – GST pitfall for mortgagee sales
Practitioner’s Viewpoint – GST rules relaxed for non-resident businesses
The Principle Purpose Test for the GST Input Tax: Is a Wide Interpretation Justified?
