(1) Online Courses: App Inventor - zero-based Android mobile application development . The course is Google courses, Professor Wu Minghui from Zhejiang University City College.
(2) Online Course: App Inventor Fun Programming Instructor: old witch App World
Everyone programming http://www.17coding.net/
Example Programming Guide and APP INVENTOR (primary) https://book1.17coding.net/
APP INVENTOR Development Collection (Intermediate) https://book2.17coding.net/
App Inventor Reference Manual https://web.17coding.net/reference/