Antique Silver Sheffield Plate 851 6 Pc Coffee/tea Set Tray
Old Sheffield Plate: An Introduction (Antique Silver Article)
Miller's Silver & Sheffield Plate Marks: Including a Guide to Makers and Styles by John Bly
Sheffield plate, its history, manufacture and art; with makers' names and marks, also a note on foreign Sheffield plate, with illustrations : Veitch, Henry Newton : Free Download, Borrow, and Streaming : Internet Archive
But it is a general rule that virtually all pieces marked 925 or sterling 925 are modern.
The silver marks most widely forged marks are generally those which have the potential for the greatest increase in value.