Income Tax Assessment Act 1997 – Sect 995.1(1): ""spouse" of an individual includes: (a) another individual (whether of the same sex or a different sex) with whom the individual is in a relationship that is registered under a * State law or * Territory law prescribed for the purposes of section 22B of the Acts Interpretation Act 1901 as a kind of relationship prescribed for the purposes of that section; and (b) another individual who, although not legally married to the individual, lives with the individual on a genuine domestic basis in a relationship as a couple."
doi.org
Cherlin, Andrew J. (2004). “The Deinstitutionalization of American Marriage”, Journal of Marriage and the Family66 (4), p. 848–61. doi:10.1111/j.0022-2445.2004.00058.x.
