diff --git a/slides/sections/0.md b/slides/sections/0.md
index 66f4569..49fc9db 100644
--- a/slides/sections/0.md
+++ b/slides/sections/0.md
@@ -20,8 +20,8 @@ mainfontoptions:
 mathfont: FiraMath-Regular
 
 references:
-  - type: article-journal
-    id: trapani15
+  - id: trapani15
+    type: article-journal
     author:
       family: Trapani
       given: Lorenzo
@@ -29,15 +29,14 @@ references:
     container-title: Journal of Econometrics
     issued:
       year: 2015
-  - type: book
-    id: silver86
+  - id: silver86
+    type: book
     author:
       family: Silverman
       given: Bernard W.
     title: Density Estimation for Statistics and Data Analysis
     issued:
       year: 1986
-
   - id: robertson74
     type: article-journal
     author:
diff --git a/slides/sections/1.md b/slides/sections/1.md
index fe81c31..aa351a7 100644
--- a/slides/sections/1.md
+++ b/slides/sections/1.md
@@ -81,18 +81,18 @@ utilized as an approximation of the former.
 
 . . .
 
-- **Properties test**:
+- **Properties test**
 
   compatibility between expected and observed PDF properties
 
 . . .
 
-- **Kolmogorov - Smirnov test**:
+- **Kolmogorov - Smirnov test**
 
   compatibility between expected and empirical CDF
 
 . . .
 
-- **Trapani test**:
+- **Trapani test**
 
   test for finite or infinite moments
diff --git a/slides/sections/4.md b/slides/sections/4.md
index e651514..6f1879b 100644
--- a/slides/sections/4.md
+++ b/slides/sections/4.md
@@ -29,6 +29,8 @@ How to estimate sample median, mode and FWHM?
 
 \End{block}
 
+. . .
+
 \setbeamercovered{}
 \begin{center}
 \begin{tikzpicture}[remember picture, >=Stealth]
@@ -139,7 +141,7 @@ How to estimate sample median, mode and FWHM?
 \begin{center}
 \begin{tikzpicture}[remember picture, overlay]
   % region
-  \draw [cyclamen, ultra thick] (f1) -- (f2);
+  \draw [ultra thick] (f1) -- (f2);
 \end{tikzpicture}
 \end{center}
 
diff --git a/slides/sections/6.md b/slides/sections/6.md
index f50b8d1..492bc6f 100644
--- a/slides/sections/6.md
+++ b/slides/sections/6.md
@@ -145,7 +145,8 @@ $$
 If $a_j$ uniformly distributed:
 
 - $\zeta_j (u)$ Bernoulli PDF with $P\left( \zeta_j (u) = 1 \right) = \frac{1}{2}$
-  $\hence E[\zeta_j]_j = \frac{1}{2} \quad \wedge \quad V[\zeta_j]_j = \frac{1}{4}$
+  $\hence \text{E}[\zeta_j]_j = \frac{1}{2}
+   \quad \wedge \quad \text{Var}[\zeta_j]_j = \frac{1}{4}$
 
 
 ## Trapani test