diff --git a/core/dbsearch.class.php b/core/dbsearch.class.php
index 6fa47c20e..9f22b796a 100644
--- a/core/dbsearch.class.php
+++ b/core/dbsearch.class.php
@@ -402,6 +402,7 @@ abstract class DBSearch
 			}
 		}
 
+		/** @var DBObjectSearch | null $oResultFilter */
 		if (!isset($oResultFilter))
 		{
 			$oKPI = new ExecutionKPI();
@@ -440,11 +441,20 @@ abstract class DBSearch
 		return $oResultFilter;
 	}
 
-	// Alternative to object mapping: the data are transfered directly into an array
-	// This is 10 times faster than creating a set of objects, and makes sense when optimization is required
 	/**
-	 * @param hash $aOrderBy Array of '[<classalias>.]attcode' => bAscending
-	 */	
+	 * Alternative to object mapping: the data are transfered directly into an array
+	 * This is 10 times faster than creating a set of objects, and makes sense when optimization is required
+	 *
+	 * @param array $aColumns
+	 * @param array $aOrderBy Array of '[<classalias>.]attcode' => bAscending
+	 * @param array $aArgs
+	 *
+	 * @return array|void
+	 * @throws \CoreException
+	 * @throws \MissingQueryArgument
+	 * @throws \MySQLException
+	 * @throws \MySQLHasGoneAwayException
+	 */
 	public function ToDataArray($aColumns = array(), $aOrderBy = array(), $aArgs = array())
 	{
 		$sSQL = $this->MakeSelectQuery($aOrderBy, $aArgs);
diff --git a/core/oql/expression.class.inc.php b/core/oql/expression.class.inc.php
index b85e6c700..c94b32c1f 100644
--- a/core/oql/expression.class.inc.php
+++ b/core/oql/expression.class.inc.php
@@ -2022,6 +2022,9 @@ class FunctionExpression extends Expression
 	}
 }
 
+/**
+ * @see https://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html
+ */
 class IntervalExpression extends Expression
 {
 	protected $m_oValue; // expression
diff --git a/core/oql/oqlinterpreter.class.inc.php b/core/oql/oqlinterpreter.class.inc.php
index 342dd8cd1..5c11761e5 100644
--- a/core/oql/oqlinterpreter.class.inc.php
+++ b/core/oql/oqlinterpreter.class.inc.php
@@ -84,7 +84,7 @@ class OqlInterpreter
 	}
 
 	/**
-	 * @return OqlQuery
+	 * @return \OqlObjectQuery|\OqlUnionQuery
 	 * @throws \OQLException
 	 */
 	public function ParseQuery()