diff --git a/Account.hs b/Account.hs
index f7d90c698..c1b3b287d 100644
--- a/Account.hs
+++ b/Account.hs
@@ -1,5 +1,7 @@
 module Account
 where
+import qualified Data.Map as Map
+
 import Utils
 import BasicTypes
 import AccountName
@@ -13,6 +15,8 @@ import Ledger
 -- and transactions (not including sub-accounts)
 type Account = (AccountName,[EntryTransaction],Amount)
 
+nullacct = ("",[],nullamt)
+
 aname (a,_,_) = a
 atransactions (_,ts,_) = ts
 abalance (_,_,b) = b
@@ -30,7 +34,7 @@ aggregateBalanceInAccountNamed l a =
     sumEntryTransactions (aggregateTransactionsInAccountNamed l a)
 
 transactionsInAccountNamed :: Ledger -> AccountName -> [EntryTransaction]
-transactionsInAccountNamed l a = 
+transactionsInAccountNamed l a =
     ledgerTransactionsMatching (["^" ++ a ++ "$"], []) l
 
 aggregateTransactionsInAccountNamed :: Ledger -> AccountName -> [EntryTransaction]
diff --git a/BasicTypes.hs b/BasicTypes.hs
index 825675640..cadb6e43e 100644
--- a/BasicTypes.hs
+++ b/BasicTypes.hs
@@ -22,7 +22,7 @@ branches = snd . node
    GOOG 500
 
    a mixed amount is one or more simple amounts:
-   $50, EUR 3, APPL 500
+   $50, EUR 3, AAPL 500
    HRS 16, $13.55, oranges 6
 
    arithmetic:
@@ -31,9 +31,9 @@ branches = snd . node
    EUR0.76 + $1 = EUR 1.52
    EUR0.76 - $1 = 0
    ($5, HRS 2) + $1 = ($6, HRS 2)
-   ($50, EUR 3, APPL 500) + ($13.55, oranges 6) = $67.51, APPL 500, oranges 6
+   ($50, EUR 3, AAPL 500) + ($13.55, oranges 6) = $67.51, AAPL 500, oranges 6
    ($50, EUR 3) * $-1 = $-53.96
-   ($50, APPL 500) * $-1 = error
+   ($50, AAPL 500) * $-1 = error
    
 -}
 
@@ -46,6 +46,8 @@ data Amount = Amount {
 
 instance Show Amount where show = showAmountRoundedOrZero
 
+nullamt = Amount "" 0
+
 showAmountRoundedOrZero :: Amount -> String
 showAmountRoundedOrZero (Amount cur qty) =
     let rounded = printf "%.2f" qty in
diff --git a/Models.hs b/Models.hs
index bc7d301ea..a4718b761 100644
--- a/Models.hs
+++ b/Models.hs
@@ -9,6 +9,8 @@ module Models (
                module Account
               )
 where
+import qualified Data.Map as Map
+
 import BasicTypes
 import AccountName
 import Entry
diff --git a/hledger.hs b/hledger.hs
index 9c7dbb1aa..2acc7de22 100644
--- a/hledger.hs
+++ b/hledger.hs
@@ -1,10 +1,10 @@
-#!/usr/bin/env runhaskell
 {-
-hledger - ledger-compatible money management utilities (& haskell study)
-GPLv3, (c) Simon Michael & contributors, 
-John Wiegley's ledger is at http://newartisans.com/ledger.html
+hledger - ledger-compatible money management tool (& haskell study)
+GPLv3, (c) Simon Michael & contributors
+inspired by John Wiegley's ledger at http://newartisans.com/ledger.html
 
-modules/models are organized roughly like this:
+modules/models are organized roughly like this; each layer can only
+reference things below it:
 
 hledger
  Options