"...a longer-term examination of debt markets reminds us that, throughout human history, regular default is more the rule than the exception. And while sovereign defaults on external, foreign-currency debt are most common, Carmen Reinhart and Kenneth Rogoff demonstrated in a paper released earlier this year...that defaults on domestic debt have happened far more often than might have been expected, particularly in times of severe economic duress."
http://www.moneyweek.com/investments/how-safe-are-government-bonds-13986.aspx
http://www.moneyweek.com/investments/how-safe-are-government-bonds-13986.aspx