diff --git a/slides/index.html b/slides/index.html
index ae925f2..2ff204d 100644
--- a/slides/index.html
+++ b/slides/index.html
@@ -28,6 +28,8 @@
         <section>
         
            <h2>A bit of context</h2>
+           
+           <p><sup>(8, 10-11)</sup></p>
           
            <img src="img/circuit.jpg" width="30%">
            <img src="img/chips.jpg" width="30%">
@@ -38,11 +40,16 @@
         
            <h2>More context</h2>
           
+          <p><sup>(7)</sup></p>
+          
            <img src="img/macro.jpg" width="50%">
 
         </section>
         <section>
           <h2>Wik'history</h2>
+          
+          <p><sup>(4)</sup></p>
+          
           <ul>
           <li><b>1958</b> - First IC (Jack Kilby, <em>Texas Instruments</em>) 🤖</li>
           <li><b>1973</b> - SPICE is born! (Laurence Nagel, <em>California</em>) 🔥</li>
@@ -56,6 +63,8 @@
         <section>
           <h2>More Wik'history</h2>
           
+          <p><sup>(1-3)</sup></p>
+          
           <p>Available technologies are <b>180nm</b> (<em>GlobalFoundries</em>), <b>130nm</b> (<em>SkyWater</em>)  and <b>90nm</b> (<em>SkyWater</em>, FDSOI).</p>
           
           <p>First used in the industry between 1999 and 2003. Old but cheap.</p>
@@ -127,6 +136,8 @@
         <section>
         
            <h2>Hello Sky130!</h2>
+           
+          <p><sup>(12)</sup></p>
           
            <img style="background-color:white;" src="img/sky130_stack.svg" height="500vh">
 
@@ -148,6 +159,8 @@
         <section>
         
            <h2>Related knowledge: Rules</h2>
+           
+          <p><sup>(12)</sup></p>
           
            <img style="background-color:white;" src="img/constraints.svg" height="500vh">
 
@@ -155,6 +168,8 @@
         <section>
         
            <h2>Related knowledge: MOSFETs</h2>
+           
+          <p><sup>(12)</sup></p>
           
            <img style="background-color:white;display:inline-block;vertical-align: middle;" src="img/fet-cross.svg" height="350vw">
            <img style="background-color:white;display:inline-block;vertical-align: middle;" src="img/fet-floor.png" height="350vh">
@@ -222,6 +237,7 @@
 [9] hello@bgjar.com, « Free svg background generator », BGJar. https://bgjar.com/ (consulté le 10 avril 2023).
 [10] J. Helebrant, microphoto of some electronics circuit board. 2021. Consulté le: 10 avril 2023. [En ligne]. Disponible sur: https://commons.wikimedia.org/wiki/File:Electronics_PCB_circuit_board_003_(51131861191).jpg
 [11] J. Helebrant, microphoto of some electronics circuit board. 2021. Consulté le: 10 avril 2023. [En ligne]. Disponible sur: https://commons.wikimedia.org/wiki/File:Electronics_PCB_circuit_board_007_(51132658884).jpg
+[12] “Welcome to SkyWater SKY130 PDK’s documentation! — SkyWater SKY130 PDK 0.0.0-356-g49d3c73 documentation.” https://skywater-pdk.readthedocs.io/en/main/ (accessed May 03, 2023).
 
            ```