diff --git a/ex-1/pdf-plot.py b/ex-1/pdf-plot.py
index db0bbc7..07209c3 100755
--- a/ex-1/pdf-plot.py
+++ b/ex-1/pdf-plot.py
@@ -1,9 +1,49 @@
 #!/usr/bin/env python
 
-from pylab import *
+from matplotlib import pyplot as plt
+import numpy as np
 import sys
 
-x, y = loadtxt(sys.stdin, unpack=True)
-title('Landau distribution', loc='right')
-plot(x, y, color='#92182b')
-show()
+
+plt.figure()
+# plt.figure(figsize=(5, 3))
+# plt.rcParams['font.size'] = 8
+
+# useful coordinates
+y_min = -0.0086     # y min axes
+y_max = 0.1895      # y max axes
+me = -0.22          # mode
+f_me = 0.1806       # f(mode)
+h_f_me = f_me/2     # falf f(mode)
+x_m = -1.5867       # x₋
+x_p = 2.4330        # x₊
+
+# prepare plot
+x, y = np.loadtxt(sys.stdin, unpack=True)
+plt.title('Landau distribution', loc='right')
+plt.xlim(-10, 10)
+plt.ylim(y_min, y_max)
+
+# draw the lines
+plt.plot([-10, me],  [f_me, f_me],     color='gray')
+plt.plot([me, me],  [f_me, y_min],     color='gray')
+plt.plot([-10, x_p], [h_f_me, h_f_me], color='gray')
+plt.plot([x_m, x_m], [y_min, h_f_me],  color='gray')
+plt.plot([x_p, x_p], [y_min, h_f_me],  color='gray')
+
+# draw the function
+plt.plot(x, y, color='#92182b')
+
+# draw the notes
+s = 0.012
+S = 0.2
+plt.annotate('$f(m_e)$',   [-10 + S, f_me - s])
+plt.annotate('$f(m_e)/2$', [-10 + S, h_f_me - s])
+plt.annotate('$x_-$',      [x_m + S, y_min + s/2])
+plt.annotate('$x_+$',      [x_p + S, y_min + s/2])
+plt.annotate('$m_e$',      [me + S, y_min + s/2])
+
+
+plt.tight_layout()
+plt.show()
+# plt.savefig('notes/images/1-notes.pdf')
diff --git a/notes/images/1-notes.pdf b/notes/images/1-notes.pdf
new file mode 100644
index 0000000..e763332
Binary files /dev/null and b/notes/images/1-notes.pdf differ
diff --git a/notes/sections/1.md b/notes/sections/1.md
index a66a2dd..9bc0878 100644
--- a/notes/sections/1.md
+++ b/notes/sections/1.md
@@ -99,29 +99,8 @@ PDF, very few parameters can be easily checked: mode, median and full width at
 half maximum (FWHM).
 
 ![Landau distribution with emphatized mode $m_e$ and
-  FWHM = ($x_+ - x_-$).](images/1-landau.pdf)
+  FWHM = ($x_+ - x_-$).](images/1-notes.pdf)
 
-\begin{figure}
-\hypertarget{fig:parameters}{%
-\begin{tikzpicture}[overlay]
-  \begin{scope}[shift={(0,0.4)}]
-  % Mode
-  \draw [thick, dashed] (7.57,3.1) -- (7.57,8.55);
-  \draw [thick, dashed] (1.9,8.55) -- (7.57,8.55);
-  \node [above right] at (7.6,3.1)  {$m_e$};
-  \node [below right] at (1.9,8.55) {$f(m_e)$};
-  % FWHM
-  \draw [thick, dashed] (1.9,5.95)  -- (9.05,5.95);
-  \draw [thick, dashed] (6.85,5.83) -- (6.85,3.1);
-  \draw [thick, dashed] (8.95,5.83)    -- (8.95,3.1);
-  \node [below right] at (1.9,5.95) {$\frac{f(m_e)}{2}$};
-  \node [above right] at (6.85,3.1) {$x_-$};
-  \node [above right] at (8.95,3.1)  {$x_+$};
-  \end{scope}
-\end{tikzpicture}}
-\end{figure}
-
-\vspace{30pt}
 
 #### Mode