diff --git a/doc/formats.md b/doc/formats.md
index 0414489..32a0482 100644
--- a/doc/formats.md
+++ b/doc/formats.md
@@ -2,7 +2,8 @@ File Formats
 ============
 
 This file documents the internal structure of various file formats
-used.
+used. Currently the basic format is used for members files and global
+configuration.
 
 Members Directory
 -----------------
diff --git a/doc/specification.md b/doc/specification.md
index df20e1b..6dd544e 100644
--- a/doc/specification.md
+++ b/doc/specification.md
@@ -1,6 +1,9 @@
 Organization Specification
 ==========================
 
+The specification of how the organization handles membership fees is
+completely wrapped inside the specification module.
+
 Modules
 -------
 
@@ -11,9 +14,18 @@ Modules
 This module contains organization specificaiton in an extensible
 format.
 
+    member-fees-lookup-table
+
+A period lookup table for full and reduced membership fees. Used by
+```lookup-member-fees``` and - more specifically -
+```lookup-member-fee``` functions in the ```members-fees``` module.
+
+    exchange-rates-lookup-table
+
+A period lookup-table for CZK/EUR conversion. Used by the
+```lookup-eur-rate``` function in the ```members-payments``` module.
+
     member-suspend-max-months
 
 Determines how many months the member can be suspended before any
 action is required.
-
-