I was looking at Arya Samaj’s translation of Vedas on onlineved.com and found that the Rig Veda is missing Mandala 7-10. Why is that? Also the way they cite the verses is quite different than the traditional method.
It's available as book. You can read this online. They mentioned Mandala, Sukta on the above of the page
https://www.elibrary.thearyasamaj.org/book/rig-veda--volume-iii#book_reader/983