May I also ask if you have any more books on embedded devices or IoT devices not specific to just Bluetooth. I'm worked on a research project I led last summer

May I also ask if you have any more books on embedded devices or IoT devices not specific to just Bluetooth. I'm worked on a research project I led last summer where I fist learned about software and hardware development for small embedded devices like microcontrollers and this year I'm working on another research project using the same technology. I feel as if I understand the technology but am not proficient with it at all. If you have any other resources let me know.