Government documents have a special kind of call number system called Superintendent of Document system (Sudoc).
Example of a Sudoc number:
S 1.1:885
You can tell a Sudoc number because it will always have a colon in it. At ACU, it will also be shelved in a special section of the library for government publications.
Sudoc does not arrange documents by subject; it arranges them by the government agency that published them. This means in order to find government documents, you want to think about the government agencies that might be involved in that area.