MGMT employees are of course allowed to buy the books they need, but prior to buying you should consider if borrowing the book from the library would be sufficient. If the library has not got the title, you can suggest that the library purchases the book for you to borrow. See library.au.dk/en/borrowing-and-returning/suggest-a-title/
If you need books for teaching purposes, please always talk to the course responsible first in order to see if the books can be obtained from the publishers who are often known to supply free books for teaching purposes.
You need approval prior to any book purchase. Please see MGMT's purchase guidelines
You are urged to use the purchase agreements negotiated by AU – but it is no longer mandatory. You can find links to AU related bookstores here:
However, the prices for AU employees are apparently very good, so please make sure not to over-pay if you order your books elsewhere.
BSS Books is still a good option, but they are not part of the purchase agreement anymore. Feel free to use them though: www.bssbooks.dk/en/home.asp