diff --git a/ch04.asciidoc b/ch04.asciidoc
index afe1626c..60f84a8d 100644
--- a/ch04.asciidoc
+++ b/ch04.asciidoc
@@ -155,9 +155,11 @@ So, for example, the following is a point P with coordinates (x,y) that is a poi
 P = (55066263022277343669578718895168534326250603453777594175500187360389116729240, 32670510020758816978083085130507043184471273380659243275938904335757337482424) 
 ----
 
-You can check this yourself using Python:
-
+<<example_4_1>> shows how you can check this yourself using Python:
 
+[[example_4_1]]
+.Using python to confirm that this point is on the elliptic curve
+====
 [source, pycon]
 ----
 Python 3.4.0 (default, Mar 30 2014, 19:23:13)
@@ -169,7 +171,7 @@ Type "help", "copyright", "credits" or "license" for more information.
 >>> (x ** 3 + 7 - y**2) % p
 0
 ----
-
+====
 
 In elliptic curve math, there is a point called the "point at infinity," which roughly corresponds to the role of 0 in addition. On computers, it's sometimes represented by x = y = 0 (which doesn't satisfy the elliptic curve equation, but it's an easy separate case that can be checked).