An open file format is used to represent the features and data associated with a spreadsheet application within a document. The file format simplifies the way a spreadsheet application organizes document features and data, and presents a logical model that is easily accessible. The file format is made...http://www.google.com.hk/patents/US20070022128?utm_source=gb-gplus-share專利 US20070022128 - Structuring data for spreadsheet documents
