12. The computer program product of claim 11 , wherein in step (b) each entry of the version control database table further includes a linking parameter indicating whether the new document may be permitted to be accessed in response to a document access request that requests access to one or more older version documents in the same document series and a maximum version difference between the latest version and the older version from which the latest version may be permitted to be accessed, wherein in step (c) the document registration request further includes a linking parameter for the new document, and wherein step (d) further includes storing the linking parameter received in step (c) in the new entry of the version control database table.
12. The computer program product of claim 11 , wherein in step (b) each entry of the version control database table further includes a linking parameter indicating whether the new document may be permitted to be accessed in response to a document access request that requests access to one or more older version documents in the same document series and a maximum version difference between the latest version and the older version from which the latest version may be permitted to be accessed, wherein in step (c) the document registration request further includes a linking parameter for the new document, and wherein step (d) further includes storing the linking parameter received in step (c) in the new entry of the version control database table. 13. The computer program product of claim 12 , wherein the process further comprises: (h) receiving a document access request from a second user to access a document, the document access request including a document ID which identifies the requested document and a user ID which is associated with the second user; (i) referring to the version control database table using the document ID to determine a version difference between the requested document and a latest version document in the same document series that the requested document belongs to; and (j) if the version difference is greater than a maximum version difference specified by the linking parameter for the latest version, referring to the stored permission information associated with the requested document to determine whether the second user has rights to access the requested document and transmitting a response to the second user based on the determination, and if the version difference is not greater than the maximum version difference, determining access rights of the second user to the requested document and the latest version document and transmitting another response to the second user based on the determination, the other response being either a response that grants access to the latest version document if the second user has access right to the latest version document regardless of whether the second user has access right to the requested document, or a response that grants access to the requested document if the second user has no access right to the latest version document but has access right to the requested document, or a response that grants no access to either the requested document or the latest version document if the second user has no access right to the latest version document and has no access right to the requested document.