Dyfyniad APA

ProQuest. (1997). ProQuest serchware for windows: Version 5.1 [Đĩa CD-ROM]. USA: Umi company.

Dyfyniad Arddull Chicago

ProQuest. ProQuest Serchware for Windows: Version 5.1 [Đĩa CD-ROM]. USA: Umi company, 1997.

Dyfyniad MLA

ProQuest. ProQuest Serchware for Windows: Version 5.1 [Đĩa CD-ROM]. USA: Umi company, 1997.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.