postdoc position does not require letter of recommendation only contact details of referees. Should I still provide the letters? I'm applying for a postdoc position at ETH Zurich. 
For the application, the following requirements are listed: 


Letter of motivation
CV and list of publications
Electronic copies of university transcripts and certificates
Contact details of two referees


They do not list letters of recommendation in their requirements. 

This leads me to the following question: 
Would it be better to provide letters of recommendation, even though they are not required? 

Additional information: 

I know the professor and he knows me. 
In fact, it would be possible to get four letters of recommendation from leading scientists. 
I know that the professor knows and respects these scientists very much. 
I'm sure that most of the other applicants would not have this strong support behind them. This would be a chance to separate me from those. However, I'm unsure if it is not counterproductive since they explicitly stated that they only need the contact information of two referees.
You do not need to provide any letters of reference.

If you do they may well be ignored as they ask for the contact details of 2 referees. This means that they will contact those referees directly and get the information required in their own format as they wish.