Which part of the exam are we referring to??? On the Part B they are from the Part B book. On the Closed Book (Part A) they are mainly from the WIT Book that you get included with the cost of the seminar and study for 3 full days at the seminar. On the Code Book (Part C) part, API 1104 in your case, they are from the API 1104 Code Book including the index, table of contents, appendixes, erratta, etc.
It never hurts to buy and study the other materials listed on the self study suggested materials list on the application download from AWS. I read through almost every one of them at least once and most twice. WIT, D1.1, and Part B I lived in for several months before the exam.
Have a Great Day, Brent