I understand that the reason why the rated voltage of the capacitor is set to about twice that of the applied power is to increase safety and reliability
Are there any papers or academic materials related to this

 

What is your actual assignment?

The use of a 2x safety factor is a design convention common in many fields of engineering and has been for hundreds of years, although the actual safety factor used various quite a bit depending on the application. What kind of papers do you think you will find?

 

Welcome to AAC!

I understand that the reason why the rated voltage of the capacitor is set to about twice that of the applied power is to increase safety and reliability

Says who? What are their credentials?

I have no problem using a capacitor rated for 6.3V in a 5V circuit. When electrolytic caps are formed, they're formed at a voltage higher than the rated voltage.