4 Bit register design with D-Flip Flop (Verilog Code included) - YouTube
VHDL Universal Shift Register
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VHDL Code for 4-Bit Shift Register
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Verilog code for Shift Register PISO, SIPO, PIPO
Verilog Programming By Naresh Singh Dobal: Design of 4 Bit Serial IN - Parallel OUT Shift Register using D_flip flop (Structural Modeling Style) Verilog CODE.
Universal Shift Register in Digital logic - GeeksforGeeks