The best way to order multiples of a single book is to back the $20 Reward Level and pledge the total amount for the number of books you want to order. ie - 9 x $20=$180
You can do this as well for collections.
You will be given the opportunity as part of the CrowdOx survey to "spend" your pledge on the books you want to purchase.
7.62 x 7.62 centimeters
Don't see the answer to your question? Ask the project creator directly.