Australian banks' stocks have further to run, despite having rallied by an average of around 20 per cent last year. Falling interest rates should continue to stimulate demand for high-yielding equities.This is the view of Citi Research, in a report published on Friday. Citi's banking analyst, Craig Williams, said: "With interest rates remaining low in 2013 and earnings expectation relatively stable, bank share pieces will continue to be well supported."With the Australian government's 10-year bond yield hovering around 3.4 per cent, prospective bank dividend yields (based on estimated 2012/13 earnings) offer an attractive spread.Citi has ANZ trading on a prospective yield of six per cent; Commonwealth Bank on 5.5 per cent; NAB on seven per cent; and Westpac on 6.5 per cent. All pay fully franked dividends.Williams said: "Bank share prices are a function of the bond yield and [of] the bank yield spread over bonds.Citi rates CBA, ANZ and Westpac as Buys.Williams said: "While CBA may appear expensive on some metrics, we believe the long-standing premium is warranted, given the bank's strong cashflow generation."Citi has a Neutral recommendation on NAB. Williams said: "We see some scope for [a] downside risk to our NAB forecasts, through topping up provisions. NAB's UK exposure remains a concern."Williams said he did not see much risk of significant deterioration in credit conditions, which would see bank share prices underperform. "Neither corporate nor household credit costs appear likely to threaten bank earnings or dividend reliability."