I'm having difficulties figuring out how to properly tag documents issued by the government.

One example is the "National Inventory Report" from the Australian Government, which should in my opinion be a book.
http://www.environment.gov.au/climate-change/greenhouse-gas-measurement/publications/national-inventory-report-2015

I has no ISBN, but is divided in three volumes, and is supposed to be updated every year.

It states the following:

"This report should be attributed as ‘National Inventory Report 2015 Volume 2, Commonwealth of Australia 2017’."

Is the "Commonwealth of Australia" supposed to be the publisher? And the author/contributor/editor field should be left blank?

Similarly, another government publication, the National Greenhouse Accounts Factors: https://www.environment.gov.au/climate-change/greenhouse-gas-measurement/publications/national-greenhouse-accounts-factors-july-2017

It is a publication that gets updated every year. It has an ISSN.
It states that it is "Published by the Department of the Environment and Energy."
But it also is "© Commonwealth of Australia 2017". Where should that copyright holder be? It is also considered a book, or should it just be a document?

Cheers