20. A method, comprising: determining a validity of a first document by simultaneously considering: textual information from the first document, textual information from a complementary document, and predefined business rules; at least one of: correcting OCR errors in the first document, and normalizing data from the first document prior to determining the validity, using at least one of the textual information from the complementary document and the predefined business rules; and outputting an indication of the determined validity.
20. A method, comprising: determining a validity of a first document by simultaneously considering: textual information from the first document, textual information from a complementary document, and predefined business rules; at least one of: correcting OCR errors in the first document, and normalizing data from the first document prior to determining the validity, using at least one of the textual information from the complementary document and the predefined business rules; and outputting an indication of the determined validity. 27. A method as recited in claim 20 , further comprising: acquiring an electronic second document; identifying a second complementary document associated with the second document; generating a list of hypotheses mapping the second document to the second complementary document using: textual information from the second document, textual information from the second complementary document, and predefined business rules; determining a validity of the second document based on the hypotheses; and outputting an indication of the determined validity of the second document.