For books, my adviser seems to like: https://www.amazon.com/VHDL-Digital-Design-Frank-Vahid/dp/0470052635/ref=sr_1_11?ie=UTF8&s=books&qid=1231766888&sr=8-11. I'm sure it has nothing to do with Frank Vahid being his old advisor... but Frank does know his stuff and his books are typically easy to follow (I have not read this book). It's obviously VHDL and not Verilog, but it's not hard to go from one language to another.
I'm currently reading through: https://www.amazon.com/gp/product/1523364025/ref=oh_aui_detailpage_o04_s03?ie=UTF8&psc=1. It's SystemVerilog, still not Verilog, but SV is a super-set of Verilog so it still may be useful. Also, if you use SV for verification you will be happy. DPI is your friend.
Hopefully this was a little helpful.
When I was in school, I used this book for my Digital Design class and found it informative and easy to digest.
VHDL for Digital Design https://www.amazon.com/dp/0470052635/ref=cm_sw_r_cp_api_i_VN41CbB0A4K71