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 up of a collection of modular parts that are stored within a container. The modular parts are logically separate but are associated with one another by one or more relationships. Each of the modular parts is capable of being interrogated separately regardless of whether or not the application that created the document is running. Each modular part is capable of having information extracted from it and copied into another document and reused. Information may also be changed, added, and deleted from each of the modular parts.