Update 009.md

book/syntax_exercises/009.md

@@ -1,6 +1,6 @@
 # Exercise 9: Cross-referencing content
 
-In this exercise, you will learn how to create references to other parts of your book, such as chapters, equations, tables, and figures. 
+In this exercise, you will learn how to create references to other parts of your book, such as chapters, sections, equations, tables, and figures.
 
 ::::::{topic} Exercise objective
 Can you create internal references to other sections, equations, tables, and figures?
@@ -24,6 +24,36 @@ For example, if you want to link to Exercise 7, you can write:
 [Go to Exercise 7](../exercises/007.md)
 ```
 
+Alternatively, you can use `{ref}` to reference a section with a target header.
+
+First, define the section you want to reference by assigning it an identifier:
+
+```md
+(exercise_1)=
+# Exercise 1: First file edit
+
+Let's start with the most basic edit: add some text to a file and see that the website is updated...
+```
+
+Then, you can reference this section in three ways:
+
+- Using the standard title text:
+  ```md
+  My favourite exercise was {ref}`exercise_1`.
+  ```
+  This will display: *My favourite exercise was Exercise 1: First file edit.*
+
+- Specifying a custom title text:
+  ```md
+  My favourite exercise was {ref}`the first one <exercise_1>`.
+  ```
+  This will display: *My favourite exercise was the first one.*
+
+- Using Markdown syntax:
+  ```md
+  My favourite exercise was [this one](exercise_1).
+  ```
+  This will display: *My favourite exercise was this one.*
 
 ## 2. Referencing an Equation
 
@@ -93,8 +123,6 @@ Figure {numref}`fig-example`
 :class: note
 
 Before moving on to the next exercise, make sure you understand the following:
-- How do you reference another chapter?
+- How do you reference another chapter or section?
 - How do you create a reference to an equation?
 - How can you refer to a table or a figure in your book?
-
-```