301a Study materials

As far as I know Philip hasn't yet published a book for the 301a exam, or any beyond the 201 for that matter. Are you a member of the LinkedIn study groups? There are good discussions on the tests there.

F5 301 Study Group

For each exam F5 provides blue prints and a study guide. I guess you know that already if you are about to attempt the 301a exam :) If not, take a look at this link : https://support.f5.com/csp/article/K29900360

Other than that, the number of F5-related third party guides/books is very low unfortunately so experience is probably your best friend here.