Most modern democracies are considered as such due to the feedback that voters do as a control of their government and country. This is done in a representative way in intervals usually of 4 years.
Some countries have additional rules to require a referendum for certain decisions, for instance changes to their constitutions or organic laws.
This has become the standard and it is assumed as the right way in many cases, but I think this is doubtful and therefore I ask.
What evidence do we have about this being enough? (with or without referendums)
If this is not enough, are there any implemented solutions that have proven to work better?
PD: BTW: I'm also interested in theoretical analyses when proved formally (since empirical proves are probably hard to obtain).