A method and apparatus for executing a transaction using a credit card includes the steps of: maintaining a credit card account associated with the credit card, the credit card account having a credit limit and a transaction balance indicative of an aggregate of previously authorized transaction amounts...http://www.google.com.hk/patents/US6038552?utm_source=gb-gplus-share專利 US6038552 - Method and apparatus to process combined credit and debit card transactions
