diff --git a/Data/HEPEVT.hs b/Data/HEPEVT.hs
--- a/Data/HEPEVT.hs
+++ b/Data/HEPEVT.hs
@@ -42,7 +42,7 @@
     , partE     = parseDouble energy
     , partM     = parseDouble mass
     , status    = statusFromInt $ read stat
-    , mothers   = (-1, Nothing)
+    , mothers   = PZero
     , iColor    = (0, 0)
     , lifetime  = 0
     , spin      = 0
diff --git a/hepevt.cabal b/hepevt.cabal
--- a/hepevt.cabal
+++ b/hepevt.cabal
@@ -1,5 +1,5 @@
 Name:                hepevt
-Version:             0.4
+Version:             0.5
 Synopsis:            HEPEVT parser
 Description:         This package implements a parser for the ASCII HEPEVT event log file format
 License:             MIT
@@ -13,7 +13,7 @@
 Library
   Default-language:    Haskell2010
   Exposed-modules:     Data.HEPEVT
-  Build-depends:       haskell2010 >= 1.0, bytestring>=0.9, lha>=0.1.1
+  Build-depends:       haskell2010 >= 1.0, bytestring>=0.9, lha>=0.1.2
   -- Other-modules:       
 
 source-repository head