Botterill George S., Keene Raymond D. The Pirc Defence

London: B.T. Batsford Limited, 1973. — 259 p. — ISBN: 978-0713403619.Published in 1973, the Pirc Defence, along with its companion volume, The Modern Defence, provide players with a wide variety of lines to play, including quality analysis that may not be in current opening books or databases.