Examples are but not limited to letters/postcards sent to the applicants, utility bills (water, energy, electricity), courier delivery notes, credit card statements (only the page contains personal information is enough i.e., name, postal address and date) that showing the same correspondence address for both applicants. You do not need to provide too much but need to make sure that the evidence provided for both applicants could cover at least the past 12 months. For instance, piece of evidence in March 2014, and another piece of evidence prior to March 2013 is sufficient.