diff --git a/Classes/PHPExcel/Shared/Date.php b/Classes/PHPExcel/Shared/Date.php
index c82c7ce..656c357 100644
--- a/Classes/PHPExcel/Shared/Date.php
+++ b/Classes/PHPExcel/Shared/Date.php
@@ -40,6 +40,13 @@ class PHPExcel_Shared_Date
 	const CALENDAR_WINDOWS_1900 = 1900;		//	Base date of 1st Jan 1900 = 1.0
 	const CALENDAR_MAC_1904 = 1904;			//	Base date of 2nd Jan 1904 = 1.0
 
+	/*
+	 * Names of the months of the year, indexed by shortname
+	 * Planned usage for locale settings
+	 *
+	 * @public
+	 * @var	string[]
+	 */
 	public static $_monthNames = array(	'Jan' => 'January',
 										'Feb' => 'February',
 										'Mar' => 'March',
@@ -54,8 +61,20 @@ class PHPExcel_Shared_Date
 										'Dec' => 'December'
 									  );
 
+	/*
+	 * Base calendar year to use for calculations
+	 *
+	 * @private
+	 * @var	int
+	 */
 	private static $ExcelBaseDate	= self::CALENDAR_WINDOWS_1900;
 
+	/*
+	 * Object type for PHP Date/Time values
+	 *
+	 * @private
+	 * @var	string
+	 */
 	public static $dateTimeObjectType	= 'DateTime';
 
 
diff --git a/Classes/PHPExcel/Shared/trend/bestFitClass.php b/Classes/PHPExcel/Shared/trend/bestFitClass.php
index bd8e629..810177a 100644
--- a/Classes/PHPExcel/Shared/trend/bestFitClass.php
+++ b/Classes/PHPExcel/Shared/trend/bestFitClass.php
@@ -35,18 +35,60 @@
  */
 class PHPExcel_Best_Fit
 {
+	/*
+	 * Indicator flag for a calculation error
+	 *
+	 * @protected
+	 * @var	boolean
+	 */
 	protected $_error				= False;
 
+	/*
+	 * Algorithm type to use for best-fit
+	 *
+	 * @protected
+	 * @var	string
+	 */
 	protected $_bestFitType			= 'undetermined';
 
+	/*
+	 * Number of entries in the sets of x- and y-value arrays
+	 *
+	 * @protected
+	 * @var	int
+	 */
 	protected $_valueCount			= 0;
 
+	/*
+	 * X-value dataseries of values
+	 *
+	 * @protected
+	 * @var	float[]
+	 */
 	protected $_xValues				= array();
 
+	/*
+	 * Y-value dataseries of values
+	 *
+	 * @protected
+	 * @var	float[]
+	 */
 	protected $_yValues				= array();
 
+	/*
+	 * X-value series of values
+	 *
+	 * @protected
+	 * @var	boolean
+	 */
 	protected $_adjustToZero		= False;
 
+	/*
+	 * Y-value series of best-fit values
+	 *
+	 * @protected
+	 * @var	float[]
+	 */
 	protected $_yBestFitValues		= array();
 
 	protected $_goodnessOfFit 		= 1;
@@ -88,11 +130,23 @@ class PHPExcel_Best_Fit
 	}	//	function getBestFitType()
 
 
+	/**
+	 * Return the Y-Value for a specified value of X
+	 *
+	 * @param	 float		$xValue			X-Value
+	 * @return	 float						Y-Value
+	 */
 	public function getValueOfYForX($xValue) {
 		return False;
 	}	//	function getValueOfYForX()
 
 
+	/**
+	 * Return the X-Value for a specified value of Y
+	 *
+	 * @param	 float		$yValue			Y-Value
+	 * @return	 float						X-Value
+	 */
 	public function getValueOfXForY($yValue) {
 		return False;
 	}	//	function getValueOfXForY()
@@ -103,11 +157,23 @@ class PHPExcel_Best_Fit
 	}	//	function getValueOfXForY()
 
 
+	/**
+	 * Return the Equation of the best-fit line
+	 *
+	 * @param	 int		$dp		Number of places of decimal precision to display
+	 * @return	 string
+	 */
 	public function getEquation($dp=0) {
 		return False;
 	}	//	function getEquation()
 
 
+	/**
+	 * Return the Slope of the line
+	 *
+	 * @param	 int		$dp		Number of places of decimal precision to display
+	 * @return	 string
+	 */
 	public function getSlope($dp=0) {
 		if ($dp != 0) {
 			return round($this->_slope,$dp);
@@ -116,6 +182,12 @@ class PHPExcel_Best_Fit
 	}	//	function getSlope()
 
 
+	/**
+	 * Return the standard error of the Slope
+	 *
+	 * @param	 int		$dp		Number of places of decimal precision to display
+	 * @return	 string
+	 */
 	public function getSlopeSE($dp=0) {
 		if ($dp != 0) {
 			return round($this->_slopeSE,$dp);
@@ -124,6 +196,12 @@ class PHPExcel_Best_Fit
 	}	//	function getSlopeSE()
 
 
+	/**
+	 * Return the Value of X where it intersects Y = 0
+	 *
+	 * @param	 int		$dp		Number of places of decimal precision to display
+	 * @return	 string
+	 */
 	public function getIntersect($dp=0) {
 		if ($dp != 0) {
 			return round($this->_intersect,$dp);
@@ -132,6 +210,12 @@ class PHPExcel_Best_Fit
 	}	//	function getIntersect()
 
 
+	/**
+	 * Return the standard error of the Intersect
+	 *
+	 * @param	 int		$dp		Number of places of decimal precision to display
+	 * @return	 string
+	 */
 	public function getIntersectSE($dp=0) {
 		if ($dp != 0) {
 			return round($this->_intersectSE,$dp);
diff --git a/Classes/PHPExcel/Shared/trend/exponentialBestFitClass.php b/Classes/PHPExcel/Shared/trend/exponentialBestFitClass.php
index bf33ec4..aaedf6c 100644
--- a/Classes/PHPExcel/Shared/trend/exponentialBestFitClass.php
+++ b/Classes/PHPExcel/Shared/trend/exponentialBestFitClass.php
@@ -41,16 +41,34 @@ class PHPExcel_Exponential_Best_Fit extends PHPExcel_Best_Fit
 	protected $_bestFitType		= 'exponential';
 
 
+	/**
+	 * Return the Y-Value for a specified value of X
+	 *
+	 * @param	 float		$xValue			X-Value
+	 * @return	 float						Y-Value
+	 */
 	public function getValueOfYForX($xValue) {
 		return $this->getIntersect() * pow($this->getSlope(),($xValue - $this->_Xoffset));
 	}	//	function getValueOfYForX()
 
 
+	/**
+	 * Return the X-Value for a specified value of Y
+	 *
+	 * @param	 float		$yValue			Y-Value
+	 * @return	 float						X-Value
+	 */
 	public function getValueOfXForY($yValue) {
 		return log(($yValue + $this->_Yoffset) / $this->getIntersect()) / log($this->getSlope());
 	}	//	function getValueOfXForY()
 
 
+	/**
+	 * Return the Equation of the best-fit line
+	 *
+	 * @param	 int		$dp		Number of places of decimal precision to display
+	 * @return	 string
+	 */
 	public function getEquation($dp=0) {
 		$slope = $this->getSlope($dp);
 		$intersect = $this->getIntersect($dp);
@@ -59,6 +77,12 @@ class PHPExcel_Exponential_Best_Fit extends PHPExcel_Best_Fit
 	}	//	function getEquation()
 
 
+	/**
+	 * Return the Slope of the line
+	 *
+	 * @param	 int		$dp		Number of places of decimal precision to display
+	 * @return	 string
+	 */
 	public function getSlope($dp=0) {
 		if ($dp != 0) {
 			return round(exp($this->_slope),$dp);
@@ -67,6 +91,12 @@ class PHPExcel_Exponential_Best_Fit extends PHPExcel_Best_Fit
 	}	//	function getSlope()
 
 
+	/**
+	 * Return the Value of X where it intersects Y = 0
+	 *
+	 * @param	 int		$dp		Number of places of decimal precision to display
+	 * @return	 string
+	 */
 	public function getIntersect($dp=0) {
 		if ($dp != 0) {
 			return round(exp($this->_intersect),$dp);
diff --git a/Classes/PHPExcel/Shared/trend/linearBestFitClass.php b/Classes/PHPExcel/Shared/trend/linearBestFitClass.php
index fa2a5ed..6b16087 100644
--- a/Classes/PHPExcel/Shared/trend/linearBestFitClass.php
+++ b/Classes/PHPExcel/Shared/trend/linearBestFitClass.php
@@ -41,16 +41,34 @@ class PHPExcel_Linear_Best_Fit extends PHPExcel_Best_Fit
 	protected $_bestFitType		= 'linear';
 
 
+	/**
+	 * Return the Y-Value for a specified value of X
+	 *
+	 * @param	 float		$xValue			X-Value
+	 * @return	 float						Y-Value
+	 */
 	public function getValueOfYForX($xValue) {
 		return $this->getIntersect() + $this->getSlope() * $xValue;
 	}	//	function getValueOfYForX()
 
 
+	/**
+	 * Return the X-Value for a specified value of Y
+	 *
+	 * @param	 float		$yValue			Y-Value
+	 * @return	 float						X-Value
+	 */
 	public function getValueOfXForY($yValue) {
 		return ($yValue - $this->getIntersect()) / $this->getSlope();
 	}	//	function getValueOfXForY()
 
 
+	/**
+	 * Return the Equation of the best-fit line
+	 *
+	 * @param	 int		$dp		Number of places of decimal precision to display
+	 * @return	 string
+	 */
 	public function getEquation($dp=0) {
 		$slope = $this->getSlope($dp);
 		$intersect = $this->getIntersect($dp);
diff --git a/Classes/PHPExcel/Shared/trend/logarithmicBestFitClass.php b/Classes/PHPExcel/Shared/trend/logarithmicBestFitClass.php
index bf649ac..3ddbd4e 100644
--- a/Classes/PHPExcel/Shared/trend/logarithmicBestFitClass.php
+++ b/Classes/PHPExcel/Shared/trend/logarithmicBestFitClass.php
@@ -41,16 +41,34 @@ class PHPExcel_Logarithmic_Best_Fit extends PHPExcel_Best_Fit
 	protected $_bestFitType		= 'logarithmic';
 
 
+	/**
+	 * Return the Y-Value for a specified value of X
+	 *
+	 * @param	 float		$xValue			X-Value
+	 * @return	 float						Y-Value
+	 */
 	public function getValueOfYForX($xValue) {
 		return $this->getIntersect() + $this->getSlope() * log($xValue - $this->_Xoffset);
 	}	//	function getValueOfYForX()
 
 
+	/**
+	 * Return the X-Value for a specified value of Y
+	 *
+	 * @param	 float		$yValue			Y-Value
+	 * @return	 float						X-Value
+	 */
 	public function getValueOfXForY($yValue) {
 		return exp(($yValue - $this->getIntersect()) / $this->getSlope());
 	}	//	function getValueOfXForY()
 
 
+	/**
+	 * Return the Equation of the best-fit line
+	 *
+	 * @param	 int		$dp		Number of places of decimal precision to display
+	 * @return	 string
+	 */
 	public function getEquation($dp=0) {
 		$slope = $this->getSlope($dp);
 		$intersect = $this->getIntersect($dp);
diff --git a/Classes/PHPExcel/Shared/trend/polynomialBestFitClass.php b/Classes/PHPExcel/Shared/trend/polynomialBestFitClass.php
index d259dda..b475ef5 100644
--- a/Classes/PHPExcel/Shared/trend/polynomialBestFitClass.php
+++ b/Classes/PHPExcel/Shared/trend/polynomialBestFitClass.php
@@ -49,6 +49,12 @@ class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit
 	}	//	function getOrder()
 
 
+	/**
+	 * Return the Y-Value for a specified value of X
+	 *
+	 * @param	 float		$xValue			X-Value
+	 * @return	 float						Y-Value
+	 */
 	public function getValueOfYForX($xValue) {
 		$retVal = $this->getIntersect();
 		$slope = $this->getSlope();
@@ -61,11 +67,23 @@ class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit
 	}	//	function getValueOfYForX()
 
 
+	/**
+	 * Return the X-Value for a specified value of Y
+	 *
+	 * @param	 float		$yValue			Y-Value
+	 * @return	 float						X-Value
+	 */
 	public function getValueOfXForY($yValue) {
 		return ($yValue - $this->getIntersect()) / $this->getSlope();
 	}	//	function getValueOfXForY()
 
 
+	/**
+	 * Return the Equation of the best-fit line
+	 *
+	 * @param	 int		$dp		Number of places of decimal precision to display
+	 * @return	 string
+	 */
 	public function getEquation($dp=0) {
 		$slope = $this->getSlope($dp);
 		$intersect = $this->getIntersect($dp);
@@ -83,6 +101,12 @@ class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit
 	}	//	function getEquation()
 
 
+	/**
+	 * Return the Slope of the line
+	 *
+	 * @param	 int		$dp		Number of places of decimal precision to display
+	 * @return	 string
+	 */
 	public function getSlope($dp=0) {
 		if ($dp != 0) {
 			$coefficients = array();
diff --git a/Classes/PHPExcel/Shared/trend/powerBestFitClass.php b/Classes/PHPExcel/Shared/trend/powerBestFitClass.php
index 11c4031..c002931 100644
--- a/Classes/PHPExcel/Shared/trend/powerBestFitClass.php
+++ b/Classes/PHPExcel/Shared/trend/powerBestFitClass.php
@@ -41,16 +41,34 @@ class PHPExcel_Power_Best_Fit extends PHPExcel_Best_Fit
 	protected $_bestFitType		= 'power';
 
 
+	/**
+	 * Return the Y-Value for a specified value of X
+	 *
+	 * @param	 float		$xValue			X-Value
+	 * @return	 float						Y-Value
+	 */
 	public function getValueOfYForX($xValue) {
 		return $this->getIntersect() * pow(($xValue - $this->_Xoffset),$this->getSlope());
 	}	//	function getValueOfYForX()
 
 
+	/**
+	 * Return the X-Value for a specified value of Y
+	 *
+	 * @param	 float		$yValue			Y-Value
+	 * @return	 float						X-Value
+	 */
 	public function getValueOfXForY($yValue) {
 		return pow((($yValue + $this->_Yoffset) / $this->getIntersect()),(1 / $this->getSlope()));
 	}	//	function getValueOfXForY()
 
 
+	/**
+	 * Return the Equation of the best-fit line
+	 *
+	 * @param	 int		$dp		Number of places of decimal precision to display
+	 * @return	 string
+	 */
 	public function getEquation($dp=0) {
 		$slope = $this->getSlope($dp);
 		$intersect = $this->getIntersect($dp);
@@ -59,6 +77,12 @@ class PHPExcel_Power_Best_Fit extends PHPExcel_Best_Fit
 	}	//	function getEquation()
 
 
+	/**
+	 * Return the Value of X where it intersects Y = 0
+	 *
+	 * @param	 int		$dp		Number of places of decimal precision to display
+	 * @return	 string
+	 */
 	public function getIntersect($dp=0) {
 		if ($dp != 0) {
 			return round(exp($this->_intersect),$dp);
diff --git a/Classes/PHPExcel/Shared/trend/trendClass.php b/Classes/PHPExcel/Shared/trend/trendClass.php
index f987831..9ea1a88 100644
--- a/Classes/PHPExcel/Shared/trend/trendClass.php
+++ b/Classes/PHPExcel/Shared/trend/trendClass.php
@@ -21,11 +21,23 @@ class trendClass
 	const TREND_BEST_FIT			= 'Bestfit';
 	const TREND_BEST_FIT_NO_POLY	= 'Bestfit_no_Polynomials';
 
+	/*
+	 * Names of the best-fit trend analysis methods
+	 *
+	 * @private
+	 * @var	string[]
+	 */
 	private static $_trendTypes = array( self::TREND_LINEAR,
 										 self::TREND_LOGARITHMIC,
 										 self::TREND_EXPONENTIAL,
 										 self::TREND_POWER
 									   );
+	/*
+	 * Names of the best-fit trend polynomial orders
+	 *
+	 * @private
+	 * @var	string[]
+	 */
 	private static $_trendTypePolyOrders = array( self::TREND_POLYNOMIAL_2,
 												  self::TREND_POLYNOMIAL_3,
 												  self::TREND_POLYNOMIAL_4,
@@ -33,6 +45,12 @@ class trendClass
 												  self::TREND_POLYNOMIAL_6
 											    );
 
+	/*
+	 * Cached results for each method when trying to identify which provides the best fit
+	 *
+	 * @private
+	 * @var	PHPExcel_Shared_Best_Fit[]
+	 */
 	private static $_trendCache = array();