Explain (citing sections where appropriate) whether the following receipts are specifically exempt from income tax?:

• Payment given by the Air Force to a member of the Air Force Reserve who undertakes services for them a few weekends a year.
• Regular maintenance payments received by a man from his ex-wife following his divorce settlement.
• Income received by a Pooled Superannuation Trust that is attributable to amounts received from a constitutionally protected fund.
• Money earned by an Australian trade union.