diff --git a/src/Microdata.php b/src/Microdata.php
index 191871b..4a3718b 100644
--- a/src/Microdata.php
+++ b/src/Microdata.php
@@ -4,7 +4,15 @@ namespace YusufKandemir\MicrodataParser;
 
 abstract class Microdata
 {
-    public static function fromHTML($html, $documentURI = '')
+    /**
+     * Creates a MicrodataParser from HTML string
+     *
+     * @param string $html HTML string to be parsed
+     * @param string $documentURI DocumentURI to be used in absolutizing URIs
+     *
+     * @return MicrodataParser
+     */
+    public static function fromHTML(string $html, string $documentURI = '') : MicrodataParser
     {
         $dom = new MicrodataDOMDocument;
         $dom->loadHTML($html, LIBXML_NOERROR);
@@ -13,7 +21,15 @@ abstract class Microdata
         return new MicrodataParser($dom);
     }
 
-    public static function fromHTMLFile($filename, $documentURI = '')
+    /**
+     * Creates a MicrodataParser from a HTML file
+     *
+     * @param string $filename Path to the file to be parsed
+     * @param string $documentURI DocumentURI to be used in absolutizing URIs
+     *
+     * @return MicrodataParser
+     */
+    public static function fromHTMLFile(string $filename, string $documentURI = '') : MicrodataParser
     {
         $dom = new MicrodataDOMDocument;
         $dom->loadHTMLFile($filename, LIBXML_NOERROR);
@@ -22,7 +38,16 @@ abstract class Microdata
         return new MicrodataParser($dom);
     }
 
-    public static function fromDOMDocument(\DOMDocument $domDocument)
+    /**
+     * Creates a MicrodataParser from a DOMDocument instance.
+     * If you have MicrodataDOMDocument then instantiate MicrodataParser class directly to avoid conversion.
+     *
+     * @param \DOMDocument $domDocument DOMDocument to be parsed.
+     * Needs to have documentURI property to be used in absolutizing URIs if wanted.
+     *
+     * @return MicrodataParser
+     */
+    public static function fromDOMDocument(\DOMDocument $domDocument) : MicrodataParser
     {
         $dom = new MicrodataDOMDocument;
         $importedNode = $dom->importNode($domDocument->documentElement, true);
diff --git a/src/MicrodataDOMDocument.php b/src/MicrodataDOMDocument.php
index 2ae375e..e9d6b35 100644
--- a/src/MicrodataDOMDocument.php
+++ b/src/MicrodataDOMDocument.php
@@ -4,13 +4,23 @@ namespace YusufKandemir\MicrodataParser;
 
 class MicrodataDOMDocument extends \DOMDocument
 {
+    /** @var \DOMXPath */
     public $xpath;
 
-    public function getItems()
+    /**
+     * Get top-level items of the document
+     *
+     * @return \DOMNodeList List of top level items as elements
+     */
+    public function getItems() : \DOMNodeList
     {
         return $this->xpath->query('//*[@itemscope and not(@itemprop)]');
     }
 
+    /**
+     * {@inheritdoc}
+     * Also assigns $xpath with DOMXPath of freshly loaded DOMDocument
+     */
     public function loadHTML($source, $options = 0)
     {
         $return = parent::loadHTML($source, $options);
@@ -20,6 +30,10 @@ class MicrodataDOMDocument extends \DOMDocument
         return $return;
     }
 
+    /**
+     * {@inheritdoc}
+     * Also assigns $xpath with DOMXPath of freshly loaded DOMDocument
+     */
     public function loadHTMLFile($filename, $options = 0)
     {
         $return = parent::loadHTMLFile($filename, $options);
diff --git a/src/MicrodataDOMElement.php b/src/MicrodataDOMElement.php
index 05493cb..ed61c34 100644
--- a/src/MicrodataDOMElement.php
+++ b/src/MicrodataDOMElement.php
@@ -4,7 +4,10 @@ namespace YusufKandemir\MicrodataParser;
 
 class MicrodataDOMElement extends \DOMElement
 {
-    public function getProperties()
+    /**
+     * @return array
+     */
+    public function getProperties() : array
     {
         $results = [];
         $memory = [$this];
@@ -45,12 +48,18 @@ class MicrodataDOMElement extends \DOMElement
         return array_reverse($results);
     }
 
-    public function hasPropertyNames()
+    /**
+     * @return bool
+     */
+    public function hasPropertyNames() : bool
     {
         return !empty($this->tokenizeAttribute('itemprop'));
     }
 
-    public function getPropertyNames()
+    /**
+     * @return array
+     */
+    public function getPropertyNames() : array
     {
         $tokens = $this->tokenizeAttribute('itemprop');
 
@@ -67,6 +76,9 @@ class MicrodataDOMElement extends \DOMElement
         return array_unique($properties);
     }
 
+    /**
+     * @return $this|string
+     */
     public function getPropertyValue()
     {
         if ($this->hasAttribute('itemscope')) {
@@ -126,11 +138,26 @@ class MicrodataDOMElement extends \DOMElement
         }
     }
 
+    /**
+     * Checks a string to see if its absolute uri or not
+     * Note: As it uses a simple regex to check, it is not that reliable
+     *
+     * @see \preg_match() for return values
+     *
+     * @param string $uri
+     *
+     * @return false|int
+     */
     protected function isAbsoluteUri(string $uri)
     {
         return preg_match("/^\w+:/", trim($uri));
     }
 
+    /**
+     * Filters out TextNodes etc. and returns child ElementNodes as array
+     *
+     * @return array Result array which contains child ElementNodes
+     */
     protected function getChildElementNodes()
     {
         $childNodes = [];
@@ -144,7 +171,14 @@ class MicrodataDOMElement extends \DOMElement
         return $childNodes;
     }
 
-    public function tokenizeAttribute($attributeName)
+    /**
+     * Tokenizes value of given attribute
+     *
+     * @param string $attributeName Name of the attribute
+     *
+     * @return array|array[]|false|string[]
+     */
+    public function tokenizeAttribute(string $attributeName)
     {
         $attribute = [];
 
@@ -155,7 +189,16 @@ class MicrodataDOMElement extends \DOMElement
         return $attribute;
     }
 
-    protected function tokenize($attribute)
+    /**
+     * Splits given attribute value in space characters to array
+     *
+     * @see \preg_split() for possible return values and behaviour
+     *
+     * @param string $attribute
+     *
+     * @return array[]|false|string[]
+     */
+    protected function tokenize(string $attribute)
     {
         return preg_split('/\s+/', trim($attribute));
     }
diff --git a/src/MicrodataParser.php b/src/MicrodataParser.php
index 4796ea5..aa534cc 100644
--- a/src/MicrodataParser.php
+++ b/src/MicrodataParser.php
@@ -4,8 +4,14 @@ namespace YusufKandemir\MicrodataParser;
 
 class MicrodataParser
 {
+    /** @var MicrodataDOMDocument */
     protected $dom;
 
+    /**
+     * MicrodataParser constructor.
+     *
+     * @param MicrodataDOMDocument $dom
+     */
     public function __construct(MicrodataDOMDocument $dom)
     {
         $dom->registerNodeClass(\DOMDocument::class, MicrodataDOMDocument::class);
@@ -14,23 +20,46 @@ class MicrodataParser
         $this->dom = $dom;
     }
 
-    public function toArray()
+    /**
+     * Extracts and converts microdata to associative array
+     *
+     * @return array
+     */
+    public function toArray() : array
     {
         // Somewhat hacky way to convert deep objects
         return json_decode(json_encode($this->extractMicrodata()), true);
     }
 
-    public function toObject()
+    /**
+     * Extracts and converts microdata to object
+     *
+     * @return \stdClass
+     */
+    public function toObject() : \stdClass
     {
         return $this->extractMicrodata();
     }
 
+    /**
+     * Extracts and converts microdata to json using \json_encode()
+     *
+     * @see \json_encode() to description of parameters and return values
+     *
+     * @param int $options
+     * @param int $depth
+     *
+     * @return false|string
+     */
     public function toJSON($options = 0, $depth = 512)
     {
         return json_encode($this->extractMicrodata(), $options, $depth);
     }
 
-    protected function extractMicrodata()
+    /**
+     * @return \stdClass
+     */
+    protected function extractMicrodata() : \stdClass
     {
         $result = new \stdClass;
 
@@ -43,7 +72,13 @@ class MicrodataParser
         return $result;
     }
 
-    protected function getObject(MicrodataDOMElement $item, $memory = [])
+    /**
+     * @param MicrodataDOMElement $item
+     * @param array $memory
+     *
+     * @return \stdClass
+     */
+    protected function getObject(MicrodataDOMElement $item, $memory = []) : \stdClass
     {
         $result = new \stdClass;
 
@@ -85,7 +120,14 @@ class MicrodataParser
         return $result;
     }
 
-    protected function isItem($element)
+    /**
+     * Check if the given parameter is a MicrodataDOMElement and has itemscope attribute
+     *
+     * @param $element
+     *
+     * @return bool
+     */
+    protected function isItem($element) : bool
     {
         return $element instanceof MicrodataDOMElement && $element->hasAttribute('itemscope');
     }