Chess Informant website Archived 2017-06-27 at the Wayback Machine, "About Us" section http://www.chessinformant.org/about-chess-informant/
David Hooper and Kenneth Whyld, The Oxford Companion to Chess (Oxford UP, 1996), p.251.
Edward Winter laments them as a "convenient research prop" that fuel ignorance of history. Kings, Commoners, and Knaves, p. 297.
John Watson, Play the French, 3d edition, p. 4; Graham Burgess, Winning with the Smith–Morra Gambit, p.4; Glenn Flear, The Ruy Lopez Main Line, p. 4.
Garry Kasparov, My Great Predecessors, Part IV, Fischer, p.493.
See, for example, Artur Yusupov, The Petroff Defence, Progress in Chess, vol. 1 (Zurich: Edition Olms, 1999); also Bruce Pandolfini, "A Fiery Cauldron of Competition," Chess Life (July 2006), p.45 (referring to the widely understood +− as "Informant speak").
Chess Informant No. 100 : ChessVibes Archived April 5, 2008, at the Wayback Machine http://www.chessvibes.com/personal/chess-informant-no-100-interview-aleksandar-matanovic/
Kasparov – picking games for the Chess Informant http://www.chessbase.com/newsdetail.asp?newsid=8028