Index: mttroot/mtt/bin/trans/dia2abg.pl
==================================================================
--- mttroot/mtt/bin/trans/dia2abg.pl
+++ mttroot/mtt/bin/trans/dia2abg.pl
@@ -510,13 +510,13 @@
 	    if (/-1/) { $effort_causality = "tail";}
 	    if (/0/) { $effort_causality = "none";}
 	    if (/1/) { $effort_causality = "head";}
 	}
 	for ($flow_causality) {
-	    if (/-1/) { $flow_causality = "tail";}
+	    if (/-1/) { $flow_causality = "head";}
 	    if (/0/) { $flow_causality = "none";}
-	    if (/1/) { $flow_causality = "head";}
+	    if (/1/) { $flow_causality = "tail";}
 	}
 		       
 	print OUT
 	    "  ## bond $mtt_bond_id \n" .
 	    "  ${diagram_name}.bonds.bond${mtt_bond_id_index{$dia_bond_id}}." .