diff --git a/src/Formatter/Coordinate/DMS.php b/src/Formatter/Coordinate/DMS.php
index <HASH>..<HASH> 100644
--- a/src/Formatter/Coordinate/DMS.php
+++ b/src/Formatter/Coordinate/DMS.php
@@ -61,7 +61,7 @@ class DMS implements FormatterInterface
     {
         $this->separator          = $separator;
         $this->useCardinalLetters = false;
-        $this->setUnits(static::UNITS_UTF8);
+        $this->setUnits(self::UNITS_UTF8);
     }
 
     /**
diff --git a/src/Formatter/Coordinate/DecimalMinutes.php b/src/Formatter/Coordinate/DecimalMinutes.php
index <HASH>..<HASH> 100644
--- a/src/Formatter/Coordinate/DecimalMinutes.php
+++ b/src/Formatter/Coordinate/DecimalMinutes.php
@@ -68,7 +68,7 @@ class DecimalMinutes implements FormatterInterface
         $this->separator          = $separator;
         $this->useCardinalLetters = false;
 
-        $this->setUnits(static::UNITS_UTF8);
+        $this->setUnits(self::UNITS_UTF8);
     }
 
     /**
don't use late static binding for class constants