--- a/HACKING.rst	Thu Jul 12 23:15:44 2012 +0300
+++ b/HACKING.rst	Thu Jul 12 23:17:22 2012 +0300
@@ -42,12 +42,61 @@
   https://sourceforge.net/p/gadict/code/
                 Sourceforge Allure interface for official repository.
 
+Dictionary source file format.
+==============================
+
+For source file format used dictd C5 file format. See::
+
+  $ man 1 dictfmt
+
+Shortly:
+
+ * Headwords was preceded by 5 or more underscore characters ``_`` and a blank
+   line.
+ * All text until the next headword is considered the definition.
+ * Any leading ``@`` characters are stripped out, but the file is
+   otherwise unchanged.
+
+For convenience also used such assumptions:
+
+ * Headwords was separated by ``;<SPACE>`` (and all was placed on single
+   line).
+ * UTF-8 encoding was used.
+ * Lines started with ``#`` striped out (comment syntax).
+ * First line with ``ABOUT:`` used as description of dictionary.
+ * First URL (line with ``http://``) used as dictionary home page.
+
 Comment syntax convention.
 ==========================
 
 As 'dictd -c5' format does not support comment syntax we filter out all
 lines that start with '#'.
 
+World wide dictionary formats and standards.
+============================================
+
+  http://en.wikipedia.org/wiki/Dictionary_writing_system
+                Dictionary writing system
+  http://www.sil.org/computing/shoebox/mdf.html
+                Multi-Dictionary Formatter (MDF). It defines about 100 data
+                field markers.
+  http://fieldworks.sil.org/flex/
+                FieldWorks Language Explorer (or FLEx, for short) is designed
+                to help field linguists perform many common language
+                documentation and analysis tasks.
+  http://code.google.com/p/lift-standard/
+                LIFT (Lexicon Interchange FormaT) is an XML format for storing
+                lexical information, as used in the creation of dictionaries.
+                It's not necessarily the format for your lexicon.
+  http://www.lexiquepro.com/
+                Lexique Pro is an interactive lexicon viewer and editor, with
+                hyperlinks between entries, category views, dictionary
+                reversal, search, and export tools. It's designed to display
+                your data in a user-friendly format so you can distribute it
+                to others.
+  http://deb.fi.muni.cz/index.php
+                DEBII — Dictionary Editor and Browser
+
 Register gadict dictionaries for dictd under Debian.
 ====================================================
 ::