diff --git a/ipynb/BASIC.ipynb b/ipynb/BASIC.ipynb
index 3569717..754eace 100644
--- a/ipynb/BASIC.ipynb
+++ b/ipynb/BASIC.ipynb
@@ -695,7 +695,7 @@
    "source": [
     "# Parsing: Grammar of Expressions\n",
     "\n",
-    "Now for the single most complicated part of the grammar: the `expression`.  The biggest complication is operator precedence: the string `\"A + B * X + C\"` should be parsed as if it were `\"A + (B * X) + C\"`, and not as `\"(A + B) * (X + C),\"` because multiplication binds more tightly than addition. There are [many schemes](https://en.wikipedia.org/wiki/Operator-precedence_parser) for parsing expressions, I'll use  [an approach](https://groups.google.com/forum/#!topic/comp.compilers/ruJLlQTVJ8o) attributed to Keith Clarke.\n",
+    "Now for the single most complicated part of the grammar: the `expression`.  The biggest complication is operator precedence: the string `\"A + B * X + C\"` should be parsed as if it were `\"A + (B * X) + C\"`, and not as `\"(A + B) * (X + C),\"` because multiplication binds more tightly than addition. There are [many schemes](https://en.wikipedia.org/wiki/Operator-precedence_parser) for parsing expressions, I'll use  [an approach](https://groups.google.com/forum/#!topic/comp.compilers/ruJLlQTVJ8o) attributed to Keith Clarke called Compact Recursive-Descent Parsing.\n",
     "\n",
     "Like all our grammatical categories, calling `expression()` pops off some tokens and returns a data object. The first thing it does is parse one of five types of simple \"primary\" expressions: \n",
     "a number like `1.23`; \n",