diff --git a/app/Models/Constraints/FormatConstraint.php b/app/Models/Constraints/FormatConstraint.php
index bfa492b..4f01e53 100644
--- a/app/Models/Constraints/FormatConstraint.php
+++ b/app/Models/Constraints/FormatConstraint.php
@@ -1,41 +1,41 @@
 <?php
 declare(strict_types=1);
 
 namespace App\Models\Constraints;
 
 use App\Models\Contracts\PropertyInterface;
 use App\Models\Contracts\StatementInterface;
 use Illuminate\Support\Collection;
 
 class FormatConstraint extends Constraint
 {
     protected $regexp;
 
     protected function init(PropertyInterface $property): void
     {
         $statements = $property->getConstraintDataByCode('format');
         if ($statements->count() !== 0) {
             /** @var Collection $qualifiers */
             $qualifiers = $statements->first()->getQualifiers();
             if ($qualifiers->count() !== 0) {
                 $this->regexp = $qualifiers->first()->getValue()->toString();
             }
         }
     }
 
     public function isSatisfiedBy(StatementInterface $statement): bool
     {
         $this->init($statement->getProperty());
 
         $value = $statement->getSnak()->getValue()->toString();
         $result = (bool)preg_match('/^' . $this->regexp . '$/', $value);
-        if ($result == false) {
+        if ($result === false) {
             $this->addViolation([
                 'value' => $value,
                 'regex' => $this->regexp,
             ]);
         }
 
         return $result;
     }
 }
diff --git a/app/Services/ConstraintService.php b/app/Services/ConstraintService.php
index eb6a8de..53b824e 100644
--- a/app/Services/ConstraintService.php
+++ b/app/Services/ConstraintService.php
@@ -1,50 +1,50 @@
 <?php
 declare(strict_types=1);
 
 namespace App\Services;
 
 use App\Models\Constraints\DistinctValuesConstraint;
 use App\Models\Contracts\ConstraintInterface;
 use App\Models\Contracts\StatementInterface;
 use Illuminate\Support\Collection;
 
 class ConstraintService
 {
     protected $constraints = [];
 
     public function __construct()
     {
         foreach (ConstraintInterface::CONSTRAINT_IDS as $constraintCode => $constraintId) {
-            $constraintClass = 'App\\Models\\Constraints\\' . camel_case($constraintCode) . 'Constraint';
+            $constraintClass = 'App\\Models\\Constraints\\' . studly_case($constraintCode) . 'Constraint';
             $this->constraints[$constraintId] = $constraintClass;
         }
     }
 
     public function getConstraintById(string $constraintId): ?ConstraintInterface
     {
         if (!\in_array($constraintId, $this->constraints)) {
             return null;
         }
 
         return new $this->constraints[$constraintId];
     }
 
     public function getStatementViolations(StatementInterface $statement): ?Collection
     {
         $property = $statement->getProperty();
 
         foreach ($this->constraints as $constraintId => $constraintClass) {
             if (!$property->hasConstraintId($constraintId)) {
                 continue;
             }
 
             /** @var ConstraintInterface $constraint */
             $constraint = new $constraintClass();
             if (!$constraint->isSatisfiedBy($statement)) {
                 return $constraint->getViolations();
             }
         }
 
         return null;
     }
 }