diff --git a/src/ZugferdDocumentPdfReader.php b/src/ZugferdDocumentPdfReader.php
index e93942d..a0f3dd6 100644
--- a/src/ZugferdDocumentPdfReader.php
+++ b/src/ZugferdDocumentPdfReader.php
@@ -17,7 +17,6 @@
 use horstoeko\zugferd\exception\ZugferdUnknownProfileParameterException;
 use horstoeko\zugferd\exception\ZugferdUnknownXmlContentException;
 use JMS\Serializer\Exception\RuntimeException;
-use Smalot\PdfParser\Parser as PdfParser;
 
 /**
  * Class representing the document reader for incoming PDF/A-Documents with
@@ -32,67 +31,45 @@
 class ZugferdDocumentPdfReader
 {
     /**
-     * List of filenames which are possible in PDF
-     */
-    public const ATTACHMENT_FILENAMES = [
-        'ZUGFeRD-invoice.xml'/*1.0*/,
-        'zugferd-invoice.xml'/*2.0*/,
-        'factur-x.xml'/*2.1*/,
-        'xrechnung.xml'
-    ];
-
-    /**
-     * Load a PDF file (ZUGFeRD/Factur-X)
+     * Tries to load a PDF file (ZUGFeRD/Factur-X) and return a ZugferdDocumentReader
      *
-     * @param  string $pdfFilename Contains a full-qualified filename which must exist and must be readable
-     * @throws Exception
+     * @param  string $pdfFilename
      * @return ZugferdDocumentReader
+     * @throws Exception
+     * @throws RuntimeException
      * @throws ZugferdFileNotFoundException
      * @throws ZugferdFileNotReadableException
      * @throws ZugferdNoPdfAttachmentFoundException
-     * @throws ZugferdUnknownXmlContentException
      * @throws ZugferdUnknownProfileException
      * @throws ZugferdUnknownProfileParameterException
-     * @throws RuntimeException
+     * @throws ZugferdUnknownXmlContentException
      */
     public static function readAndGuessFromFile(string $pdfFilename): ZugferdDocumentReader
     {
-        if (!file_exists($pdfFilename)) {
-            throw new ZugferdFileNotFoundException($pdfFilename);
-        }
-
-        $pdfContent = file_get_contents($pdfFilename);
-
-        if ($pdfContent === false) {
-            throw new ZugferdFileNotReadableException($pdfFilename);
-        }
-
-        return static::readAndGuessFromContent($pdfContent);
+        return ZugferdDocumentPdfReaderExt::readAndGuessFromFile($pdfFilename);
     }
 
     /**
      * Tries to load an attachment content from PDF and return a ZugferdDocumentReader
      *
-     * @param  string $pdfContent String containing the binary pdf data
+     * @param  string $pdfContent
      * @return ZugferdDocumentReader
      * @throws Exception
+     * @throws RuntimeException
      * @throws ZugferdNoPdfAttachmentFoundException
-     * @throws ZugferdUnknownXmlContentException
      * @throws ZugferdUnknownProfileException
      * @throws ZugferdUnknownProfileParameterException
-     * @throws RuntimeException
+     * @throws ZugferdUnknownXmlContentException
      */
     public static function readAndGuessFromContent(string $pdfContent): ZugferdDocumentReader
     {
-        $xmlContent = static::internalExtractXMLFromPdfContent($pdfContent);
-
-        return ZugferdDocumentReader::readAndGuessFromContent($xmlContent);
+        return ZugferdDocumentPdfReaderExt::readAndGuessFromContent($pdfContent);
     }
 
     /**
      * Returns a XML content from a PDF file
      *
-     * @param  string $pdfFilename Contains a full-qualified filename which must exist and must be readable
+     * @param  string $pdfFilename
      * @return string
      * @throws Exception
      * @throws ZugferdFileNotFoundException
@@ -101,23 +78,12 @@ public static function readAndGuessFromContent(string $pdfContent): ZugferdDocum
      */
     public static function getXmlFromFile(string $pdfFilename): string
     {
-        if (!file_exists($pdfFilename)) {
-            throw new ZugferdFileNotFoundException($pdfFilename);
-        }
-
-        $pdfContent = file_get_contents($pdfFilename);
-
-        if ($pdfContent === false) {
-            throw new ZugferdFileNotReadableException($pdfFilename);
-        }
-
-        return static::getXmlFromContent($pdfContent);
+        return ZugferdDocumentPdfReaderExt::getInvoiceDocumentContentFromFile($pdfFilename);
     }
 
     /**
      * Returns a XML content from a PDF binary stream (string)
      *
-     * @param  string $pdfContent String Containing the binary pdf data
      * @param  string $pdfContent
      * @return string
      * @throws Exception
@@ -125,50 +91,6 @@ public static function getXmlFromFile(string $pdfFilename): string
      */
     public static function getXmlFromContent(string $pdfContent): string
     {
-        return static::internalExtractXMLFromPdfContent($pdfContent);
-    }
-
-    /**
-     * Get the attachment content from XML.
-     * See the allowed filenames which are supported
-     *
-     * @param  string $pdfContent
-     * @return string
-     * @throws Exception
-     * @throws ZugferdNoPdfAttachmentFoundException
-     */
-    protected static function internalExtractXMLFromPdfContent(string $pdfContent): string
-    {
-        $pdfParser = new PdfParser();
-        $pdfParsed = $pdfParser->parseContent($pdfContent);
-        $filespecs = $pdfParsed->getObjectsByType('Filespec');
-
-        $attachmentFound = false;
-        $attachmentIndex = 0;
-        $embeddedFileIndex = 0;
-
-        foreach ($filespecs as $filespec) {
-            $filespecDetails = $filespec->getDetails();
-            if (in_array($filespecDetails['F'], static::ATTACHMENT_FILENAMES)) {
-                $attachmentFound = true;
-                break;
-            }
-            $attachmentIndex++;
-        }
-
-        if (true == $attachmentFound) {
-            /**
-             * @var array<\Smalot\PdfParser\PDFObject>
-             */
-            $embeddedFiles = $pdfParsed->getObjectsByType('EmbeddedFile');
-            foreach ($embeddedFiles as $embeddedFile) {
-                if ($attachmentIndex == $embeddedFileIndex) {
-                    return $embeddedFile->getContent();
-                }
-                $embeddedFileIndex++;
-            }
-        }
-
-        throw new ZugferdNoPdfAttachmentFoundException();
+        return ZugferdDocumentPdfReaderExt::getInvoiceDocumentContentFromContent($pdfContent);
     }
 }