diff --git a/README.rst b/README.rst
index cb5ca8f..d488b98 100644
--- a/README.rst
+++ b/README.rst
@@ -1,13 +1,14 @@
 RPI_SGP30
 =========
 
-Program to read eCO_2 and TVOC from the `SGP30 sensor <https://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/9_Gas_Sensors/Sensirion_Gas_Sensors_SGP30_Datasheet_EN.pdf>`_. Based on the smbus2 i2c library for ease of use.
+Library to read |eCO_2| and TVOC from the `SGP30 sensor <https://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/9_Gas_Sensors/Sensirion_Gas_Sensors_SGP30_Datasheet_EN.pdf>`_. Based on the smbus2 i2c library for ease of use.
 
 
 Quick usage-example:
 --------------------
 ::
 
+    from smbus2 import SMBusWrapper
     from sgp30 import Sgp30
     import time
     with SMBusWrapper(1) as bus:
@@ -35,5 +36,6 @@ Features that are known to be missing (listing in rough order of importance):
 
 Hardware notices:
 -----------------
-If you have the AdaFruit board with built in level shifters and voltage regulator it is should work if you just plug in `SDA to pin 3, SCL to pin 5, VCC to pin 17 and GND to pin 20 <https://pinout.xyz/pinout/i2c>`_. You should then be able to find the SGP30 an address 0x58 using `i2cdetect -y 1`. If you get an error message  you probbably need to enable i2c in the kernel using  `raspi-config and reboot <https://learn.sparkfun.com/tutorials/raspberry-pi-spi-and-i2c-tutorial>`_
+If you have the Adafruit board with built in level shifters and voltage regulator it is should work if you just plug in `SDA to pin 3, SCL to pin 5, VCC to pin 17 and GND to pin 20 <https://pinout.xyz/pinout/i2c>`_. You should then be able to find the SGP30 an address 0x58 using `i2cdetect -y 1`. If you get an error message  you probably need to enable i2c in the kernel using  `raspi-config and reboot <https://learn.sparkfun.com/tutorials/raspberry-pi-spi-and-i2c-tutorial>`_
 
+.. |eCO_2| replace:: eCO\ :sub:`2`