diff --git a/OptimizeRenderingWithPostGIS.md b/OptimizeRenderingWithPostGIS.md
index 1aadd40..90d01ea 100644
--- a/OptimizeRenderingWithPostGIS.md
+++ b/OptimizeRenderingWithPostGIS.md
@@ -214,7 +214,7 @@ If there is any active connection Postgresql will wait until it is closed, so if
 ## Use an extent parameter
 If an extent parameter is not set, mapnik will perform a query like this...
 
-```
+```sql
 SELECT ST_XMin(ext),ST_YMin(ext),ST_XMax(ext),ST_YMax(ext)
 FROM (SELECT ST_Extent(geom) as ext from planet_osm_line) as tmp
 ```
@@ -222,7 +222,10 @@ FROM (SELECT ST_Extent(geom) as ext from planet_osm_line) as tmp
 ...which requires PostGIS to walk the entire result set of the queried table each time the DataSource is used for the first time in a rendering session.  There are three parameters available for use to avoid this process:
 
 ### extent_from_subquery
-E.g. `<Parameter name="extent_from_subquery">true</Parameter>`
+E.g.
+```xml
+<Parameter name="extent_from_subquery">true</Parameter>
+```
 
 **Pros:**
 * Precise estimate of extent
@@ -239,7 +242,10 @@ E.g. `<Parameter name="extent_from_subquery">true</Parameter>`
 * tile server where render requests return small features sets or any render requests with large feature sets are pre-rendered and cached
 
 ### extent
-E.g. `<Parameter name="extent">-20037508,-19929239,20037508,19929239</Parameter>`
+E.g.
+```xml
+<Parameter name="extent">-20037508,-19929239,20037508,19929239</Parameter>
+```
 
 **Pros:**
 * No database overhead
@@ -259,7 +265,10 @@ E.g. `<Parameter name="extent">-20037508,-19929239,20037508,19929239</Parameter>
 * Seldom changing result set with few updates
 
 ### estimate_extent
-E.g. `<Parameter name="estimate_extent">true</Parameter>`
+E.g.
+```xml
+<Parameter name="estimate_extent">true</Parameter>
+```xml
 
 **Pros:**
 * Faster than not setting any extent parameters; significantly for large result sets