Document searching method using forward and backward citation tables

Claim 2

A computer-implemented document searching method for searching a plurality of documents registered in a computer system for a desired one thereof, comprising the steps of: searching a first link information table, which links said plurality of registered documents to referred documents cited in the plurality of registered documents, for a referred document cited in a specified one of said plurality of registered documents; and searching a second link information table, which links together those of said plurality of registered documents that cite a referred document in common with each other, for any of the registered documents that cite the searched referred document cited in the specified one of said plurality of registered documents.

Claim 3

A document searching method as set forth in claim 1, wherein said first and second link information tables are recorded in a recording means that also stores said registered documents.

Claim 4

A computer-implemented document registering method for registering documents in a document database in a computer system, comprising the steps of: creating a first link information table linking registered documents to referred documents cited in said registered documents by extracting titles of said referred documents from the registered documents; creating a second link information table linking together those of said registered documents that cite a referred document in common with each other, by exchanging entries of said first link information table and sorting the exchanged first link information table for referred documents; and registering said first and second link information tables.

Claim 5

A computer-implemented document registering method for registering documents in a document database in a computer system, comprising the steps of: creating a first link information table linking registered documents to referred documents cited in said registered documents by extracting titles of said referred documents from the registered documents; creating a second link information table linking together those of said registered documents that cite a referred document in common with each other, by exchanging entries of said first link information table and sorting the exchanged first link information table for referred documents; and registering said first and second link information tables.

Claim 6

A document registering method as set forth in claim 3, wherein said first and second link information tables are recorded in a recording means that also stores said registered documents.

Claim 7

A computer-implemented document searching method for searching a plurality of documents registered in a document database in a computer system, comprising: a referred document identification step of extracting a character string corresponding to a logical structure of a referred document from a document specified by a searcher, to identify a title of the referred document from said character string; and a document search step of searching said registered documents for the title obtained in said referred document identification step, with use of searching data linking said registered documents to referred documents cited in said registered documents.

Claim 8

A computer-implemented document searching method for searching a plurality of documents registered in a document database in a computer system, comprising: a referred document identification step of extracting a character string corresponding to a logical structure of a referred document from a document specified by a searcher, to identify a title of the referred document from said character string; and a document search step of searching said registered documents for the title obtained in said referred document identification step, with use of searching data linking said registered documents to referred documents cited in said registered documents.

Claim 9

A document searching method as set forth in claim 5, wherein said character string is previously extracted from the registered document and said searching data is created based on the extracted character string.

Claim 10

A document searching method as set forth in claim 6, wherein said registered documents have a logical structure and the character string corresponding to the logical structure of the referred document is extracted from said registered document with use of said logical structure.

Claim 11

A document searching method as set forth in claim 7, wherein said extraction of the character string corresponding to the logical structure of the referred document is carried out by extracting a featured character string from said logical structure.

Claim 12

A document database, stored in a computer-readable storage medium, for registering therein documents as text data, and searching data for searching a referred document cited in said registered documents.

Claim 13

A document database, stored in a computer-readable storage medium, for registering therein documents as text data, and searching data for searching a referred document cited in said registered documents.

Claim 14

A document database as set forth in claim 9, wherein said searching data includes a character string corresponding to a logical structure of the referred documents cited in the registered documents.

Claim 15

A computer-implemented document searching system for searching a plurality of documents previously registered in a computer system, comprising: record means for recording therein a first link information table, which links said registered documents to referred documents cited in the plurality of registered documents, and a second link information table, which links together those of said plurality of registered documents that cite a referred document in common with each other; specification means for specifying a desired one of the registered documents by a user; means for extracting a referred document cited in said specified registered document from said document database with use of said first link information table; and means for extracting one of said plurality of registered documents that cites said extracted referred document with use of said second link information table.

Claim 16

A computer-implemented document searching system for searching a plurality of documents previously registered in a computer system, comprising: record means for recording therein a first link information table, which links said registered documents to referred documents cited in the plurality of registered documents, and a second link information table, which links together those of said plurality of registered documents that cite a referred document in common with each other; specification means for specifying a desired one of the registered documents by a user; means for extracting a referred document cited in said specified registered document from said document database with use of said first link information table; and means for extracting one of said plurality of registered documents that cites said extracted referred document with use of said second link information table.

Claim 17

A computer-implemented document registering and searching method for registering and searching a plurality of documents in a computer system, comprising the steps of: creating a first link information table linking registered documents to referred documents cited in said registered documents by extracting titles of said referred documents from the registered documents; creating a second link information table linking together those of said registered documents that cite a referred document in common with each other, by exchanging entries of said first link information table and sorting the exchanged first link information table for referred documents; registering said first and second link information tables; searching said first link information table for one of said referred documents cited in a specified one of said plurality of registered documents; and searching a second link information table for any of the registered documents that cite the searched referred document cited in the specified one of said plurality of registered documents.

Claim 18

A computer-implemented document registering and searching method for registering and searching a plurality of documents in a computer system, comprising the steps of: creating a first link information table linking registered documents to referred documents cited in said registered documents by extracting titles of said referred documents from the registered documents; creating a second link information table linking together those of said registered documents that cite a referred document in common with each other, by exchanging entries of said first link information table and sorting the exchanged first link information table for referred documents; registering said first and second link information tables; searching said first link information table for one of said referred documents cited in a specified one of said plurality of registered documents; and searching a second link information table for any of the registered documents that cite the searched referred document cited in the specified one of said plurality of registered documents.

Claim 19

A document management method for managing a plurality of documents registered in a computer system and for searching for a related document using the computer system, comprising the steps of: (a) when registering one or more documents in the computer system: assigning a document number unique in the computer system to each of the registered documents; adding a record including the assigned document number, a file name of a file storing the document, and a title of the document to a document management information table, for each of the registered documents; extracting reference titles from the registered documents; obtaining a document number corresponding to each of the extracted reference titles by referring to the document management information table; adding a record including the assigned document number and the obtained document number to a referred document table, for each of the obtained document numbers; and making a related document table including records containing a first registered document number and a second registered document number, the document corresponding to the second document number referring to the document corresponding to the first document number, by exchanging item positions of the referred document table and by sorting for the first document number; (b) when a document search is instructed by a user: searching the referred document table to find the referred document number of the referred document indicated by the user; searching the related document table to find a related document number referring to the searched referred document number; and outputting the searched referred document number and the searched related document number with corresponding information in the document management information table.

Claim 20

A document management method for managing a plurality of documents registered in a computer system and for searching for a related document using the computer system, comprising the steps of: (a) when registering one or more documents in the computer system: assigning a document number unique in the computer system to each of the registered documents; adding a record including the assigned document number, a file name of a file storing the document, and a title of the document to a document management information table, for each of the registered documents; extracting reference titles from the registered documents; obtaining a document number corresponding to each of the extracted reference titles by referring to the document management information table; adding a record including the assigned document number and the obtained document number to a referred document table, for each of the obtained document numbers; and making a related document table including records containing a first registered document number and a second registered document number, the document corresponding to the second document number referring to the document corresponding to the first document number, by exchanging item positions of the referred document table and by sorting for the first document number; (b) when a document search is instructed by a user: searching the referred document table to find the referred document number of the referred document indicated by the user; searching the related document table to find a related document number referring to the searched referred document number; and outputting the searched referred document number and the searched related document number with corresponding information in the document management information table.