Adding references to Readme

Readme.md

@@ -875,12 +875,12 @@ Finally, the debouncing methods are called in the main method of Keyboard, which
 
 #### Simple_Implementation
 
-There are two example implementation codes, the first one (Simple_Implementation), allows for the creation of a simple user interface, with two example menus, three graphs and two modifiers.
+There are two example implementation codes, the first one (Simple_Implementation), allows for the creation of a simple user interface, with two example menus, three graphs and two modifiers[^1].
 The library already includes the creation of the Adafruit_SSD1306 object as display. It can be modified to match other display controllers.
 
     Adafruit_SSD1306 display(DISP_WIDTH, DISP_HEIGHT, &Wire, -1);
 
-In the example provided, an integer variable *i* is declared to test the graphs. Furthermore, two integer variables are created to test the modifiers.
+In the example provided, an integer variable *i* is declared to test the graphs. Furthermore, two integer variables are created to test the modifiers[^2].
 
     int i = 0;
     int multiplier = 1;