I particularly like Statistical Inference by George Casella and Roger Lee Berger.
You could also look at Introduction to Probability by Joseph K. Blitzstein and Jessica Hwang (available for free here: http://probabilitybook.net (redirects to drive)).
string product{"not worked"} is initializing the string product to "not worked".
It's the same as std::string product; product = "not worked";
[&](job& my_job) { } is a lambda expression. & is capturing the variable by reference. my_job is the parameter being passed which is a pointer of type job.