There is no international book rate.
I would call and ask if media rate is available for int'l shipping. Would take longer but be much cheaper. Otherwise would find at the P.O. a priority flat rate box that would hold all of the books and check the rate online. This will be much cheaper, and be a fixed rate regardless of weight. If you package it your own box it will be a rate based on weight and destination which I wouldn't know without asking a clerk at the p.o. Make sure you fill out a customs form too.
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