I did a lot of research on this at one point, and these are what I ended up going with and was quite pleased. You can probably find them cheaper at abe books or somewhere, I'm just linking amazon for the ease (hopefully amazon links are allowed)
I hate read comments here, because they are always AIDS. People arguing about whether non technical people know what a zip file is for example. But this comment was a shiny diamond in a pile of turd, thank you.
I have the exact same thing happen to me. I'll talk to someone from a diff area code that I never get robo calls from, and then bam, robo calls from that area code.
its not blacklist and whitelist because "black=bad, white=good", black is the abscense of light, hence the light is blocked, white would obviously be the opposite. So its black because you are blocking things, and white because you aren't.
https://www.amazon.com/Calculus-4th-Michael-Spivak/dp/091409...
https://www.amazon.com/Combined-Answer-Calculus-Fourth-Editi...