Verilog is a hardware description language used to describe digital electronic circuits. Verilog is also called Verilog HDL where HDL is an abbreviation for High Description Language.
Digital Design (Verilog): An Embedded Systems Approach Using Verilog
The Verilog PLI Handbook: A User's Guide and Comprehensive Reference on the Verilog Programming Language Interface (Springer International Series in Engineering and Computer Science)