diff --git a/reference/stats/functions/stats-cdf-poisson.xml b/reference/stats/functions/stats-cdf-poisson.xml
index b66d0b2941..fa4a344ce1 100644
--- a/reference/stats/functions/stats-cdf-poisson.xml
+++ b/reference/stats/functions/stats-cdf-poisson.xml
@@ -13,9 +13,49 @@
    <methodparam><type>float</type><parameter>par2</parameter></methodparam>
    <methodparam><type>int</type><parameter>which</parameter></methodparam>
   </methodsynopsis>
-
-  &warn.undocumented.func;
-
+  <para>
+   Returns the cumulative distribution function, its inverse, or one of its parameters, of the Poisson distribution.
+   The kind of the return value and parameters (<parameter>par1</parameter> and <parameter>par2</parameter>) are
+   determined by <parameter>which</parameter>.
+  </para>
+  <para>
+   The following table lists the return value and parameters by <parameter>which</parameter>.
+   CDF, x, and lambda denotes cumurative distribution function, the value of the random variable,
+   and the parameter of the Poisson distribution, respectively.
+   <table>
+    <title>Return value and parameters</title>
+    <tgroup cols="4">
+     <thead>
+      <row>
+       <entry><parameter>which</parameter></entry>
+       <entry>Return value</entry>
+       <entry><parameter>par1</parameter></entry>
+       <entry><parameter>par2</parameter></entry>
+      </row>
+     </thead>
+     <tbody>
+      <row>
+       <entry>1</entry>
+       <entry>CDF</entry>
+       <entry>x</entry>
+       <entry>lambda</entry>
+      </row>
+      <row>
+       <entry>2</entry>
+       <entry>x</entry>
+       <entry>CDF</entry>
+       <entry>lambda</entry>
+      </row>
+      <row>
+       <entry>3</entry>
+       <entry>lambda</entry>
+       <entry>x</entry>
+       <entry>CDF</entry>
+      </row>
+     </tbody>
+    </tgroup>
+   </table>
+  </para>
  </refsect1>
  <refsect1 role="parameters">
   &reftitle.parameters;
@@ -25,6 +65,7 @@
      <term><parameter>par1</parameter></term>
      <listitem>
       <para>
+       The first parameter
       </para>
      </listitem>
     </varlistentry>
@@ -32,6 +73,7 @@
      <term><parameter>par2</parameter></term>
      <listitem>
       <para>
+       The second parameter
       </para>
      </listitem>
     </varlistentry>
@@ -39,6 +81,7 @@
      <term><parameter>which</parameter></term>
      <listitem>
       <para>
+       The flag to determine what to be calculated
       </para>
      </listitem>
     </varlistentry>
@@ -47,8 +90,8 @@
  </refsect1>
 
  <refsect1 role="returnvalues">
-  &reftitle.returnvalues;
   <para>
+   Returns CDF, x, or lambda, determined by <parameter>which</parameter>.
   </para>
  </refsect1>
 
diff --git a/reference/stats/functions/stats-dens-normal.xml b/reference/stats/functions/stats-dens-normal.xml
index 6d59192fd7..8053d8e3fa 100644
--- a/reference/stats/functions/stats-dens-normal.xml
+++ b/reference/stats/functions/stats-dens-normal.xml
@@ -3,7 +3,7 @@
 <refentry xml:id="function.stats-dens-normal" xmlns="http://docbook.org/ns/docbook">
  <refnamediv>
   <refname>stats_dens_normal</refname>
-  <refpurpose>Not documented</refpurpose>
+  <refpurpose>Probability density function of the normal distribution</refpurpose>
  </refnamediv>
  <refsect1 role="description">
   &reftitle.description;
@@ -13,9 +13,12 @@
    <methodparam><type>float</type><parameter>ave</parameter></methodparam>
    <methodparam><type>float</type><parameter>stdev</parameter></methodparam>
   </methodsynopsis>
-
-  &warn.undocumented.func;
-
+  <para>
+   Returns the probability density at <parameter>x</parameter>, where the
+   random variable follows the normal distribution of which the mean is
+   <parameter>ave</parameter> and the standard deviation is
+   <parameter>stdev</parameter>.
+  </para>
  </refsect1>
  <refsect1 role="parameters">
   &reftitle.parameters;
@@ -25,6 +28,7 @@
      <term><parameter>x</parameter></term>
      <listitem>
       <para>
+       The value at which the probability density is calculated
       </para>
      </listitem>
     </varlistentry>
@@ -32,6 +36,7 @@
      <term><parameter>ave</parameter></term>
      <listitem>
       <para>
+       The mean of the distribution
       </para>
      </listitem>
     </varlistentry>
@@ -39,6 +44,7 @@
      <term><parameter>stdev</parameter></term>
      <listitem>
       <para>
+       The standard deviation of the distribution
       </para>
      </listitem>
     </varlistentry>
@@ -49,6 +55,7 @@
  <refsect1 role="returnvalues">
   &reftitle.returnvalues;
   <para>
+   The probability density at <parameter>x</parameter> or &false; for failure.
   </para>
  </refsect1>