Added doubled word warnings.
diff --git a/Doc/ref/ref3.tex b/Doc/ref/ref3.tex
index 36c8c38..2ab1a01 100644
--- a/Doc/ref/ref3.tex
+++ b/Doc/ref/ref3.tex
@@ -1740,7 +1740,7 @@
indexes by the built-in sequence types, and the \method{__*item__()}
methods are expected to do this as well. However, since they should
already be doing that, negative indexes cannot be passed in; they must
-be be constrained to the bounds of the sequence before being passed to
+be constrained to the bounds of the sequence before being passed to
the \method{__*item__()} methods.
Calling \code{max(0, i)} conveniently returns the proper value.