diff --git a/callagent/MGCPCallAgent.st b/callagent/MGCPCallAgent.st
index e4ef808..d577725 100644
--- a/callagent/MGCPCallAgent.st
+++ b/callagent/MGCPCallAgent.st
@@ -16,10 +16,6 @@
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 "
 
-PackageLoader
-    fileInPackage: 'Sockets';
-    fileInPackage: 'OsmoNetwork'.
-
 Object subclass: MGCPCallAgentBase [
     | net trunks sem addr port |
     <category: 'OsmoMGCP-Callagent'>
diff --git a/callagent/MGCPLogArea.st b/callagent/MGCPLogArea.st
index abdd439..4811423 100644
--- a/callagent/MGCPLogArea.st
+++ b/callagent/MGCPLogArea.st
@@ -16,8 +16,6 @@
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 "
 
-PackageLoader fileInPackage: #OsmoLogging.
-
 Osmo.LogArea subclass: MGCPLogArea [
     <category: 'OsmoMGCP-Logging'>
 
diff --git a/callagent/MGCPTransaction.st b/callagent/MGCPTransaction.st
index cd994ec..3ecb3f4 100644
--- a/callagent/MGCPTransaction.st
+++ b/callagent/MGCPTransaction.st
@@ -16,10 +16,6 @@
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 "
 
-PackageLoader
-    fileInPackage: 'Sockets';
-    fileInPackage: 'OsmoCore'.
-
 Object subclass: MGCPTransactionBase [
     | callagent t_retransmit t_expire t_remove sem |
     <comment: 'I handle timers for the transaction'>
diff --git a/grammar/MGCPGrammar.st b/grammar/MGCPGrammar.st
index 936419a..3a97058 100644
--- a/grammar/MGCPGrammar.st
+++ b/grammar/MGCPGrammar.st
@@ -16,8 +16,6 @@
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 "
 
-PackageLoader fileInPackage: 'PetitParser'.
-
 PP.PPCompositeParser subclass: MGCPGrammar [
     | MGCPMessage EOL One_WSP MGCPMessage MGCPCommandLine MGCPVerb transaction_id endpointName MGCPversion MGCPParameter MGCPCommand ParameterValue SDPRecord SDPLine SDPinformation MGCPResponseLine responseCode responseString packageName wordParser |
     <category: 'OsmoMGCP-Core'>
diff --git a/grammar/MGCPGrammarTest.st b/grammar/MGCPGrammarTest.st
index 4e91e63..4a9acff 100644
--- a/grammar/MGCPGrammarTest.st
+++ b/grammar/MGCPGrammarTest.st
@@ -16,8 +16,6 @@
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 "
 
-PackageLoader fileInPackage: 'PetitParserTests'.
-
 PP.PPCompositeParserTest subclass: MGCPGrammarTest [
     <comment: 'I test some parts of the grammar'>
     <category: 'OsmoMGCP-Core-Tests'>
diff --git a/package.xml b/package.xml
index ffcf9bd..5c02b35 100644
--- a/package.xml
+++ b/package.xml
@@ -2,8 +2,11 @@
     <name>OsmoMGCP</name>
     <namespace>Osmo</namespace>
 
+    <prereq>Sockets</prereq>
+    <prereq>PetitParser</prereq>
     <prereq>OsmoLogging</prereq>
     <prereq>OsmoCore</prereq>
+    <prereq>OsmoNetwork</prereq>
     <filein>grammar/MGCPGrammar.st</filein>
 
     <filein>callagent/MGCPCallAgent.st</filein>
@@ -16,6 +19,7 @@
     <filein>callagent/MGCPParser.st</filein>
 
     <test>
+        <prereq>PetitParserTests</prereq>
         <sunit>Osmo.MGCPGrammarTest</sunit>
         <sunit>Osmo.MGCPCommandTest</sunit>
         <sunit>Osmo.MGCPEndpointAllocTest</sunit>