diff --git a/src/GeoIP2/Record/AbstractPlaceRecord.php b/src/GeoIP2/Record/AbstractPlaceRecord.php
index 2726c62..54800d1 100644
--- a/src/GeoIP2/Record/AbstractPlaceRecord.php
+++ b/src/GeoIP2/Record/AbstractPlaceRecord.php
@@ -4,5 +4,16 @@ namespace GeoIP2\Record;
 
 abstract class AbstractPlaceRecord extends AbstractRecord
 {
+  private $languages;
 
+  public function __construct($record, $languages){
+    $this->languages = $languages;
+    parent::__construct($record);
+  }
+
+  public function name() {
+    foreach($this->languages as $language) {
+      if (isset($this->names[$language])) return $this->names[$language];
+    }
+  }
 }
\ No newline at end of file
diff --git a/src/GeoIP2/Record/AbstractRecord.php b/src/GeoIP2/Record/AbstractRecord.php
index 09da27d..e1aae72 100644
--- a/src/GeoIP2/Record/AbstractRecord.php
+++ b/src/GeoIP2/Record/AbstractRecord.php
@@ -11,8 +11,13 @@ abstract class AbstractRecord
   }
 
   public function __get($attr) {
-    if (isset($this->record[$attr])) return $this->record[$attr];
-
-    throw new RuntimeException("Unknown attribute: $attr");
+    $valid = in_array($attr, $this->validAttributes);
+    if ($valid && isset($this->record[$attr])){
+      return $this->record[$attr];
+    } elseif ($valid) {
+      return null;
+    } else {
+      throw new \RuntimeException("Unknown attribute: $attr");
+    }
   }
 }
\ No newline at end of file
diff --git a/src/GeoIP2/Record/City.php b/src/GeoIP2/Record/City.php
index 9a1454e..fe000ec 100644
--- a/src/GeoIP2/Record/City.php
+++ b/src/GeoIP2/Record/City.php
@@ -4,5 +4,5 @@ namespace GeoIP2\Record;
 
 class City extends AbstractPlaceRecord
 {
-
+  protected $validAttribute = Array('confidence', 'geoname_id', 'names');
 }
\ No newline at end of file
diff --git a/src/GeoIP2/Record/Continent.php b/src/GeoIP2/Record/Continent.php
index efb0373..7a1967b 100644
--- a/src/GeoIP2/Record/Continent.php
+++ b/src/GeoIP2/Record/Continent.php
@@ -4,5 +4,7 @@ namespace GeoIP2\Record;
 
 class Continent extends AbstractPlaceRecord
 {
-
+  protected $validAttributes = Array('continent_code',
+                                     'geoname_id',
+                                     'names');
 }
\ No newline at end of file
diff --git a/src/GeoIP2/Record/Country.php b/src/GeoIP2/Record/Country.php
index 07f8d59..7af965a 100644
--- a/src/GeoIP2/Record/Country.php
+++ b/src/GeoIP2/Record/Country.php
@@ -5,17 +5,8 @@ namespace GeoIP2\Record;
 class Country extends AbstractPlaceRecord
 {
 
-  private $languages;
-
-  public function __construct($record, $languages){
-    $this->languages = $languages;
-    parent::__construct($record);
-  }
-
-  public function name() {
-    foreach($this->languages as $language) {
-      if (isset($this->names[$language])) return $this->names[$language];
-    }
-  }
-
+  protected $validAttributes = Array('confidence',
+                                   'geoname_id',
+                                   'iso_code',
+                                   'names');
 }
\ No newline at end of file
diff --git a/src/GeoIP2/Record/Location.php b/src/GeoIP2/Record/Location.php
index dde5aeb..208ce0e 100644
--- a/src/GeoIP2/Record/Location.php
+++ b/src/GeoIP2/Record/Location.php
@@ -4,5 +4,11 @@ namespace GeoIP2\Record;
 
 class Location extends AbstractRecord
 {
-
+  protected $validAttributes = Array('accuracy_radius',
+                                     'latitude',
+                                     'longitude',
+                                     'metro_code',
+                                     'postal_code',
+                                     'postal_confidence',
+                                     'time_zone');
 }
\ No newline at end of file
diff --git a/src/GeoIP2/Record/Postal.php b/src/GeoIP2/Record/Postal.php
index 80e0693..bfd9344 100644
--- a/src/GeoIP2/Record/Postal.php
+++ b/src/GeoIP2/Record/Postal.php
@@ -4,5 +4,5 @@ namespace GeoIP2\Record;
 
 class Postal extends AbstractRecord
 {
-
+  protected $validAttributes = Array('code', 'confidence');
 }
diff --git a/src/GeoIP2/Record/RepresentedCountry.php b/src/GeoIP2/Record/RepresentedCountry.php
index b8c83f1..9368d84 100644
--- a/src/GeoIP2/Record/RepresentedCountry.php
+++ b/src/GeoIP2/Record/RepresentedCountry.php
@@ -4,5 +4,9 @@ namespace GeoIP2\Record;
 
 class RepresentedCountry extends Country
 {
-
+  protected $validAttributes = Array('confidence',
+                                   'geoname_id',
+                                   'iso_code',
+                                   'names',
+                                   'type');
 }
\ No newline at end of file
diff --git a/src/GeoIP2/Record/Subdivision.php b/src/GeoIP2/Record/Subdivision.php
index 0da51f1..dbe5301 100644
--- a/src/GeoIP2/Record/Subdivision.php
+++ b/src/GeoIP2/Record/Subdivision.php
@@ -4,5 +4,8 @@ namespace GeoIP2\Record;
 
 class Subdivision extends AbstractPlaceRecord
 {
-
+  protected $validAttributes = Array('confidence',
+                                     'geoname_id',
+                                     'iso_code',
+                                     'names');
 }
\ No newline at end of file
diff --git a/src/GeoIP2/Record/Traits.php b/src/GeoIP2/Record/Traits.php
index a7bcdc0..6aac032 100644
--- a/src/GeoIP2/Record/Traits.php
+++ b/src/GeoIP2/Record/Traits.php
@@ -4,5 +4,14 @@ namespace GeoIP2\Record;
 
 class Traits extends AbstractRecord
 {
+  protected $validAttributes = Array('autonomous_system_number',
+                                     'autonomous_system_organization',
+                                     'domain',
+                                     'is_anonymous_proxy',
+                                     'is_satellite_provider',
+                                     'isp',
+                                     'ip_address',
+                                     'organization',
+                                     'user_type');
 
 }
\ No newline at end of file