For Greg Withers & Anna Maria Bligh
"Ms Bligh and her family have lived in South Brisbane for more than 20 years. She is married to Greg Withers, a senior public servant, with whom she has two sons (Joe b. 1987 and Oliver b. 1993)." ... "Biography taken from: Premier's Web Site"
The ONLY source found that gives the sons' birth years. Its wording is identical to the Australian Women's Register entry except for the parenthesised years, and the page states it reproduces the Queensland Premier's own website biography - so the register and this page are one origin, the official biography, not two. The years 1987 and 1993 are the basis for the birthDate fills in this proposal.