Funding beyond discounting: collateralagreements and derivatives pricing

apparently ground-breaking article by vladimir piterbarg, the head of barcap quantitative research and author of a well-known 3 volume series on interest rate modeling. http://www.scribd.com/doc/34328165/Risk-Magazine-Piterbarg-Funding-Beyond-Discounting-Collateral-Agreements-and-Derivatives-Pricing important for correctly valuing derivatives, and what the 'risk-free' rate really is.