diff --git a/src/1_einstein_model.md b/src/1_einstein_model.md
index 151c17710fd8c65329a147fa469cb7ef0c4e84cc..ae615fb5d2fe65acfa8fb9e01e372011246e8434 100644
--- a/src/1_einstein_model.md
+++ b/src/1_einstein_model.md
@@ -63,8 +63,6 @@ So there is:
 
 This can be explained by considering a _quantum_ harmonic oscillator:
 
-![Wave functions and energies of a harmonic oscillator](figures/harmonic.svg)
-
 ```python
 import math
 from numpy.polynomial.hermite import Hermite
@@ -120,7 +118,7 @@ for i in range(no_states):
     
     
     # annotate plot
-    ax.text(x[len(x)-1], h0_ener(i)+1/4, '$\Psi_%2i (x)$' %(i), 
+    ax.text(x[len(x)-1], h0_ener(i)+1/4, r'$\Psi_%2i (x)$' %(i), 
              horizontalalignment='center', fontsize=14)
     
     ax.text(1/4, h0_ener(i)+1/4, '$E_%2i$' %(i), 
@@ -134,7 +132,7 @@ for i in range(no_states):
                     xytext=(x[0]+1/2, h0_ener(i)), 
                     arrowprops=dict(arrowstyle="<->"))
     elif i==1:
-        ax.text(x[0]+1/4, h0_ener(i-1)+1/3, '$\hbar\omega$', 
+        ax.text(x[0]+1/4, h0_ener(i-1)+1/3, r'$\hbar\omega$', 
                  horizontalalignment='center', fontsize=14)
         
         ax.annotate("", xy=(x[0]+1/2, h0_ener(i)), 
@@ -156,8 +154,8 @@ ax.set_yticklabels([])
 ax.set_xticklabels([])
 
 # Set x and y labels
-ax.set_xlabel('X '+'($\sqrt{\hbar/m\omega}$)', fontsize=12)
-ax.set_ylabel('E '+'($\hbar\omega$)', fontsize=12)
+ax.set_xlabel('X '+ r'($\sqrt{\hbar/m\omega}$)', fontsize=12)
+ax.set_ylabel('E '+ r'($\hbar\omega$)', fontsize=12)
 ax.yaxis.set_label_coords(0.5,1)
 ```