Hi,
I plan to study Network Operation program in WGU. They requires 14 certificates, I have achieved 5 certificates. Due to a tight budget, I plan to get as many as I can so I don't have to spend much money for the degree

My next certificate would be CCNA Security. I already have background knowledge from CCENT, CCNA R&S, Network+, Security+. I read on Amazon's review and threads in techexams and learned that Official Cisco Guide is not enough for the exam. Some suggest to read Cisco ASA: All-in-one Next-Generation Firewall (3rd Edition), which is 1200 pages. Is it an overkill for CCNA Sec?
My plan is to use:
Cisco ASA: All-in-one Next-Generation Firewall
31 Days Before Your CCNA Security Exam
My English listening skill is not good so I am no really into video training.
Please help me to choose learning material for this exam.
Thank you for your help!
Best,
Huy.