Ruy Lopez Books

Schliemann or Jaenisch gambit is not an opening for those who have a faint heart. The positions one has to defend are difficult for both players as the early middle game will be a razor sharp fight where neither side can expect a draw.

Andrew Martin analyzes Geller - Kuzmin 2002 ("The Lopez Grip, part II") with the variation 4. d3 that used to be played by patzers. Nowadays even strong grandmasters seem to play the line with white and every black player who is willing to play the Schliemann/Jaenisch must be prepared for this line.