diff --git a/src/Common/FacturaeSigner.php b/src/Common/FacturaeSigner.php
index 4f1a18b..9b69cde 100644
--- a/src/Common/FacturaeSigner.php
+++ b/src/Common/FacturaeSigner.php
@@ -13,6 +13,27 @@ final class FacturaeSigner {
   const SIGN_POLICY_NAME = 'Política de Firma FacturaE v3.1';
   const SIGN_POLICY_URL = 'http://www.facturae.es/politica_de_firma_formato_facturae/politica_de_firma_formato_facturae_v3_1.pdf';
   const SIGN_POLICY_DIGEST = 'Ohixl6upD6av8N7pEvDABhEL6hM=';
+  const ALLOWED_OID_TYPES = [
+    // Mandatory fields in https://datatracker.ietf.org/doc/html/rfc4514#section-3
+    'CN'     => 'CN',
+    'L'      => 'L',
+    'ST'     => 'ST',
+    'O'      => 'O',
+    'OU'     => 'OU',
+    'C'      => 'C',
+    'STREET' => 'STREET',
+    'DC'     => 'DC',
+    'UID'    => 'UID',
+
+    // Other fields with well-known names
+    'GN' => 'GN',
+    'SN' => 'SN',
+
+    // Other fields with compatibility issues
+    'organizationIdentifier' => 'OID.2.5.4.97',
+    'serialNumber'           => 'OID.2.5.4.5',
+    'title'                  => 'OID.2.5.4.12',
+  ];
 
   use KeyPairReaderTrait;
 
@@ -45,7 +66,7 @@ final class FacturaeSigner {
   public $timestampId;
 
   /**
-   * Class constuctor
+   * Class constructor
    */
   public function __construct() {
     $this->regenerateIds();
@@ -72,7 +93,7 @@ public function regenerateIds() {
 
   /**
    * Set signing time
-   * @param  int|string $time Time of the signature as UNIX timestamp or parseable date
+   * @param  int|string $time Time of the signature as UNIX timestamp or parsable date
    * @return self             This instance
    */
   public function setSigningTime($time) {
@@ -154,10 +175,17 @@ public function sign($xml) {
     $signingTime = ($this->signingTime === null) ? time() : $this->signingTime;
     $certData = openssl_x509_parse($this->publicChain[0]);
     $certIssuer = [];
-    foreach ($certData['issuer'] as $item=>$value) {
-      $certIssuer[] = "$item=$value";
+    foreach ($certData['issuer'] as $item=>$rawValues) {
+      if (!array_key_exists($item, self::ALLOWED_OID_TYPES)) {
+        continue;
+      }
+      $item = self::ALLOWED_OID_TYPES[$item];
+      $values = is_array($rawValues) ? $rawValues : [$rawValues];
+      foreach ($values as $value) {
+        $certIssuer[] = "$item=$value";
+      }
     }
-    $certIssuer = implode(',', array_reverse($certIssuer));
+    $certIssuer = implode(', ', array_reverse($certIssuer));
     $xadesSignedProperties = '<xades:SignedProperties Id="'. $this->signatureSignedPropertiesId . '">' .
       '<xades:SignedSignatureProperties>' .
         '<xades:SigningTime>' . date('c', $signingTime) . '</xades:SigningTime>' .
diff --git a/src/Common/XmlTools.php b/src/Common/XmlTools.php
index 1782f20..d8f46e3 100644
--- a/src/Common/XmlTools.php
+++ b/src/Common/XmlTools.php
@@ -119,7 +119,7 @@ public static function toBase64($bytes, $pretty=false) {
   /**
    * Prettify
    * @param  string $input Input string
-   * @return string        Multi-line resposne
+   * @return string        Multi-line response
    */
   private static function prettify($input) {
     return chunk_split($input, 76, "\n");
diff --git a/src/CorrectiveDetails.php b/src/CorrectiveDetails.php
index 3a38529..d5a99f5 100644
--- a/src/CorrectiveDetails.php
+++ b/src/CorrectiveDetails.php
@@ -35,13 +35,13 @@ class CorrectiveDetails {
   public $reasonDescription = null;
 
   /**
-   * Start of tax period (as UNIX timestamp or parseable date string)
+   * Start of tax period (as UNIX timestamp or parsable date string)
    * @var string|int|null
    */
   public $taxPeriodStart = null;
 
   /**
-   * End of tax period (as UNIX timestamp or parseable date string)
+   * End of tax period (as UNIX timestamp or parsable date string)
    * @var string|int|null
    */
   public $taxPeriodEnd = null;
diff --git a/src/Extensions/FacturaeExtension.php b/src/Extensions/FacturaeExtension.php
index c50267b..73ab121 100644
--- a/src/Extensions/FacturaeExtension.php
+++ b/src/Extensions/FacturaeExtension.php
@@ -1,6 +1,8 @@
 <?php
 namespace josemmo\Facturae\Extensions;
 
+use josemmo\Facturae\Facturae;
+
 abstract class FacturaeExtension {
   private $fac;
 
diff --git a/src/Face/SoapClient.php b/src/Face/SoapClient.php
index 7790a3d..368f7e2 100644
--- a/src/Face/SoapClient.php
+++ b/src/Face/SoapClient.php
@@ -44,8 +44,8 @@ protected abstract function getWebNamespace();
 
   /**
    * Send SOAP request
-   * @param  string           $body Request body
-   * @return SimpleXMLElement       Response
+   * @param  string            $body Request body
+   * @return \SimpleXMLElement       Response
    */
   protected function request($body) {
     // Generate random IDs for this request
diff --git a/src/Face/Traits/FaceTrait.php b/src/Face/Traits/FaceTrait.php
index 33a3557..774ed5a 100644
--- a/src/Face/Traits/FaceTrait.php
+++ b/src/Face/Traits/FaceTrait.php
@@ -2,6 +2,7 @@
 namespace josemmo\Facturae\Face\Traits;
 
 use josemmo\Facturae\Common\XmlTools;
+use josemmo\Facturae\FacturaeFile;
 
 trait FaceTrait {
   /**
@@ -15,7 +16,7 @@ protected function getWebNamespace() {
 
   /**
    * Get invoice status codes
-   * @return SimpleXMLElement Response
+   * @return \SimpleXMLElement Response
    */
   public function getStatus() {
     return $this->request('<web:consultarEstados></web:consultarEstados>');
@@ -24,8 +25,8 @@ public function getStatus() {
 
   /**
    * Get administrations
-   * @param  boolean          $onlyTopLevel Get only top level administrations
-   * @return SimpleXMLElement               Response
+   * @param  boolean           $onlyTopLevel Get only top level administrations
+   * @return \SimpleXMLElement               Response
    */
   public function getAdministrations($onlyTopLevel=true) {
     $tag = "consultarAdministraciones";
@@ -36,8 +37,8 @@ public function getAdministrations($onlyTopLevel=true) {
 
   /**
    * Get units
-   * @param  string|null      $code Administration code
-   * @return SimpleXMLElement       Response
+   * @param  string|null       $code Administration code
+   * @return \SimpleXMLElement       Response
    */
   public function getUnits($code=null) {
     if (is_null($code)) return $this->request('<web:consultarUnidades></web:consultarUnidades>');
@@ -49,8 +50,8 @@ public function getUnits($code=null) {
 
   /**
    * Get NIFs
-   * @param  string|null      $code Administration code
-   * @return SimpleXMLElement       Response
+   * @param  string|null       $code Administration code
+   * @return \SimpleXMLElement       Response
    */
   public function getNifs($code=null) {
     if (is_null($code)) return $this->request('<web:consultarNIFs></web:consultarNIFs>');
@@ -62,8 +63,8 @@ public function getNifs($code=null) {
 
   /**
    * Get invoice
-   * @param  string|string[]  $regId Invoice register ID(s)
-   * @return SimpleXMLElement        Response
+   * @param  string|string[]   $regId Invoice register ID(s)
+   * @return \SimpleXMLElement        Response
    */
   public function getInvoices($regId) {
     if (is_string($regId)) {
@@ -80,10 +81,10 @@ public function getInvoices($regId) {
 
   /**
    * Send invoice
-   * @param  string           $email       Email address
-   * @param  FacturaeFile     $invoice     Invoice
-   * @param  FacturaeFile[]   $attachments Attachments
-   * @return SimpleXMLElement              Response
+   * @param  string            $email       Email address
+   * @param  FacturaeFile      $invoice     Invoice
+   * @param  FacturaeFile[]    $attachments Attachments
+   * @return \SimpleXMLElement              Response
    */
   public function sendInvoice($email, $invoice, $attachments=array()) {
     $req = '<web:enviarFactura><request>';
@@ -109,9 +110,9 @@ public function sendInvoice($email, $invoice, $attachments=array()) {
 
   /**
    * Cancel invoice
-   * @param  string           $regId  Invoice register ID
-   * @param  string           $reason Cancelation reason
-   * @return SimpleXMLElement         Response
+   * @param  string            $regId  Invoice register ID
+   * @param  string            $reason Cancellation reason
+   * @return \SimpleXMLElement         Response
    */
   public function cancelInvoice($regId, $reason) {
     return $this->request('<web:anularFactura>' .
diff --git a/src/Face/Traits/Faceb2bTrait.php b/src/Face/Traits/Faceb2bTrait.php
index a4494d9..37084b5 100644
--- a/src/Face/Traits/Faceb2bTrait.php
+++ b/src/Face/Traits/Faceb2bTrait.php
@@ -2,6 +2,8 @@
 namespace josemmo\Facturae\Face\Traits;
 
 use josemmo\Facturae\Common\XmlTools;
+use josemmo\Facturae\FacturaeFile;
+use SimpleXMLElement;
 
 trait Faceb2bTrait {
   /**
@@ -116,8 +118,8 @@ public function downloadInvoice($regId, $validate=true) {
 
   /**
    * Confirm invoice download
-   * @param  string           $regId   Registry number
-   * @return SimpleXMLElement          Response
+   * @param  string           $regId Registry number
+   * @return SimpleXMLElement        Response
    */
   public function confirmInvoiceDownload($regId) {
     return $this->request('<web:ConfirmInvoiceDownload><request>' .
@@ -147,8 +149,8 @@ public function rejectInvoice($regId, $reason, $comment=null) {
 
   /**
    * Mark invoice as paid
-   * @param  string           $regId   Registry number
-   * @return SimpleXMLElement          Response
+   * @param  string           $regId Registry number
+   * @return SimpleXMLElement        Response
    */
   public function markInvoiceAsPaid($regId) {
     return $this->request('<web:MarkInvoiceAsPaid><request>' .
@@ -159,8 +161,8 @@ public function markInvoiceAsPaid($regId) {
 
   /**
    * Accept invoice cancellation
-   * @param  string           $regId   Registry number
-   * @return SimpleXMLElement          Response
+   * @param  string           $regId Registry number
+   * @return SimpleXMLElement        Response
    */
   public function acceptInvoiceCancellation($regId) {
     return $this->request('<web:AcceptInvoiceCancellation><request>' .
diff --git a/src/Facturae.php b/src/Facturae.php
index d292831..10ec12d 100644
--- a/src/Facturae.php
+++ b/src/Facturae.php
@@ -10,7 +10,7 @@
  * Class for creating electronic invoices that comply with the Spanish FacturaE format.
  */
 class Facturae {
-  const VERSION = "1.7.8";
+  const VERSION = "1.7.9";
   const USER_AGENT = "FacturaePHP/" . self::VERSION;
 
   const SCHEMA_3_2 = "3.2";
@@ -33,43 +33,43 @@ class Facturae {
   const PRECISION_LINE = 1;
   const PRECISION_INVOICE = 2;
 
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_CASH = "01";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_DEBIT = "02";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_RECEIPT = "03";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_TRANSFER = "04";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_ACCEPTED_BILL_OF_EXCHANGE = "05";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_DOCUMENTARY_CREDIT = "06";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_CONTRACT_AWARD = "07";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_BILL_OF_EXCHANGE = "08";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_TRANSFERABLE_IOU = "09";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_IOU = "10";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_CHEQUE = "11";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_REIMBURSEMENT = "12";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_SPECIAL = "13";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_SETOFF = "14";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_POSTGIRO = "15";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_CERTIFIED_CHEQUE = "16";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_BANKERS_DRAFT = "17";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_CASH_ON_DELIVERY = "18";
-  /** @deprecated 1.7.3 Use constants from @see{FacturaePayment} class instead. */
+  /** @deprecated 1.7.3 Use constants from {@see FacturaePayment} class instead. */
   const PAYMENT_CARD = "19";
 
   const TAX_IVA = "01";
diff --git a/src/FacturaePayment.php b/src/FacturaePayment.php
index a8ca0a4..ef4047a 100644
--- a/src/FacturaePayment.php
+++ b/src/FacturaePayment.php
@@ -34,7 +34,7 @@ class FacturaePayment {
   public $method = self::TYPE_CASH;
 
   /**
-   * Payment due date (as UNIX timestamp or parseable date string)
+   * Payment due date (as UNIX timestamp or parsable date string)
    * @var int|string|null
    */
   public $dueDate = null;
diff --git a/src/FacturaeTraits/ExportableTrait.php b/src/FacturaeTraits/ExportableTrait.php
index 6b7c4d3..1f07184 100644
--- a/src/FacturaeTraits/ExportableTrait.php
+++ b/src/FacturaeTraits/ExportableTrait.php
@@ -2,18 +2,20 @@
 namespace josemmo\Facturae\FacturaeTraits;
 
 use josemmo\Facturae\Common\XmlTools;
-use josemmo\Facturae\CorrectiveDetails;
+use josemmo\Facturae\Facturae;
 use josemmo\Facturae\FacturaePayment;
 use josemmo\Facturae\ReimbursableExpense;
 
 /**
  * Allows a Facturae instance to be exported to XML.
+ *
+ * @var Facturae $this
  */
 trait ExportableTrait {
 
   /**
    * Add optional fields
-   * @param  object   $item   Subject item
+   * @param  array    $item   Subject item
    * @param  string[] $fields Optional fields
    * @return string           Output XML
    */
@@ -43,7 +45,6 @@ public function export($filePath=null) {
     // Prepare document
     $xml = '<fe:Facturae xmlns:fe="' . self::$SCHEMA_NS[$this->version] . '">';
     $totals = $this->getTotals();
-    /** @var CorrectiveDetails|null */
     $corrective = $this->getCorrective();
     $paymentDetailsXML = $this->getPaymentDetailsXML($totals);
 
diff --git a/src/FacturaeTraits/PropertiesTrait.php b/src/FacturaeTraits/PropertiesTrait.php
index f62a1f2..5702480 100644
--- a/src/FacturaeTraits/PropertiesTrait.php
+++ b/src/FacturaeTraits/PropertiesTrait.php
@@ -2,8 +2,10 @@
 namespace josemmo\Facturae\FacturaeTraits;
 
 use josemmo\Facturae\CorrectiveDetails;
+use josemmo\Facturae\Facturae;
 use josemmo\Facturae\FacturaeFile;
 use josemmo\Facturae\FacturaeItem;
+use josemmo\Facturae\FacturaeParty;
 use josemmo\Facturae\FacturaePayment;
 use josemmo\Facturae\ReimbursableExpense;
 
@@ -11,6 +13,8 @@
  * Implements all attributes and methods needed to make Facturae instantiable.
  * This includes all properties that define an electronic invoice, but without
  * additional functionalities such as signing or exporting.
+ *
+ * @var Facturae $this
  */
 trait PropertiesTrait {
   protected $currency = "EUR";
@@ -593,6 +597,7 @@ public function addCharge($reason, $value, $isPercentage=true) {
       "rate"   => $isPercentage ? $value : null,
       "amount" => $isPercentage ? null   : $value
     );
+    return $this;
   }
 
 
@@ -622,6 +627,7 @@ public function clearCharges() {
    */
   public function setRelatedInvoice($relatedInvoice) {
     $this->header['relatedInvoice'] = $relatedInvoice;
+    return $this;
   }
 
 
@@ -671,6 +677,7 @@ public function addAttachment($file, $description=null) {
       "file" => $file,
       "description" => $description
     );
+    return $this;
   }
 
 
diff --git a/src/FacturaeTraits/SignableTrait.php b/src/FacturaeTraits/SignableTrait.php
index 65b1791..23a7032 100644
--- a/src/FacturaeTraits/SignableTrait.php
+++ b/src/FacturaeTraits/SignableTrait.php
@@ -2,10 +2,13 @@
 namespace josemmo\Facturae\FacturaeTraits;
 
 use josemmo\Facturae\Common\FacturaeSigner;
+use josemmo\Facturae\Facturae;
 
 /**
  * Implements all properties and methods needed for an instantiable
  * Facturae to be signed and time stamped.
+ *
+ * @var Facturae $this
  */
 trait SignableTrait {
   /** @var FacturaeSigner|null */
diff --git a/src/FacturaeTraits/UtilsTrait.php b/src/FacturaeTraits/UtilsTrait.php
index 858435c..02dea57 100644
--- a/src/FacturaeTraits/UtilsTrait.php
+++ b/src/FacturaeTraits/UtilsTrait.php
@@ -1,8 +1,13 @@
 <?php
 namespace josemmo\Facturae\FacturaeTraits;
 
+use josemmo\Facturae\Extensions\FacturaeExtension;
+use josemmo\Facturae\Facturae;
+
 /**
- * Implements utilitary methods for an instantiable Facturae.
+ * Implements utility methods for an instantiable Facturae.
+ *
+ * @var Facturae $this
  */
 trait UtilsTrait {
   protected $extensions = array();
@@ -48,8 +53,8 @@ public function pad($val, $field, $precision=null) {
 
   /**
    * Get extension
-   * @param  string    $name Extension name or class name
-   * @return Extension       Extension instance
+   * @param  string            $name Extension name or class name
+   * @return FacturaeExtension       Extension instance
    */
   public function getExtension($name) {
     $topNamespace = explode('\\', __NAMESPACE__);
diff --git a/src/ReimbursableExpense.php b/src/ReimbursableExpense.php
index 353019a..710cd02 100644
--- a/src/ReimbursableExpense.php
+++ b/src/ReimbursableExpense.php
@@ -15,7 +15,7 @@ class ReimbursableExpense {
   public $buyer = null;
 
   /**
-   * Issue date (as UNIX timestamp or parseable date string)
+   * Issue date (as UNIX timestamp or parsable date string)
    * @var string|int|null
    */
   public $issueDate = null;