I am looking for the citation above
I’m not sure what you are looking for, but there is the following (FYI the first letter of his service number seems to be the letter “O” instead of the number “0”): https://www.awm.gov.au/collection/R1518057
It refers to the following mention in the 2 April 1970 Gazette: https://trove.nla.gov.au/newspaper/article/241049202?searchTerm=Tardent
The story behind his 1970 Vietnam decoration: https://trove.nla.gov.au/newspaper/article/259476795?searchTerm=michael