diff --git a/mode7_demo/docs/mode7_demo.tex b/mode7_demo/docs/mode7_demo.tex
index f232b4c8..a55fcbe6 100644
--- a/mode7_demo/docs/mode7_demo.tex
+++ b/mode7_demo/docs/mode7_demo.tex
@@ -487,6 +487,9 @@ the 6502.
 A typical implementation takes around 700 cycles
 for a 8.8 x 8.8 fixed point multiply.
 
+% Note, this is Quarter-square multiplication, apparently an ancient algorithm
+% https://en.wikipedia.org/wiki/Multiplication_algorithm#Quarter_square_multiplication
+
 We improved this by using the fast multiply algorithm
 described by Stephen Judd.