diff --git a/README.org b/README.org
index c77b806..0346687 100644
--- a/README.org
+++ b/README.org
@@ -3193,7 +3193,16 @@ non-interactive =org-element= functions to an =Emacs-lisp= buffer.
 [[https://www.masteringemacs.org/][Mickey Peterson]] has posted [[https://www.masteringemacs.org/article/correcting-typos-misspellings-abbrev][Correcting Typos and Misspellings with Abbrev]] showing
 how to use [[info:emacs#Keyboard Macros][Keyboard Macros (info)]] to exploit [[https://en.wikipedia.org/wiki/Wikipedia:Lists_of_common_misspellings/For_machines][Wikipedia's list of common
 misspellings for machines]].  Listing [[lst:misspellings-abbrev]] defines his
-keyboard macro under the name =misspellings-abrev=.
+keyboard macro under the name =misspellings-abrev=.  I have used those
+directions to define src_emacs-lisp{global-abbrev-table} and to store it in
+src_emacs-lisp{abbrev-file-name} for git management.  I can change the
+abbreviation definitions in this file by means of:
+1. Execute src_emacs-lisp{(edit-abbrevs)} to alter abbreviation definitions by
+   editing an =*Abbrevs*= buffer.
+2. Add, edit, or remove definitions of the form ="source" 1 "target"= under the
+   global or a mode-specific table.
+3. Execute src_emacs-lisp{(abbrev-edit-save-buffer)} to save all user
+   abbreviation definitions in the current buffer.
 
 #+caption[Definition of the =misspellings-abbrev= keyboard macro]:
 #+caption: Definition of the =misspellings-abbrev= keyboard macro.
diff --git a/etc/abbrev.el b/etc/abbrev.el
index e5b4110..a775db2 100644
--- a/etc/abbrev.el
+++ b/etc/abbrev.el
@@ -4086,3 +4086,10 @@
     ("zeebra" "zebra" nil :count 1)
    ))
 
+(define-abbrev-table 'org-mode-abbrev-table
+  '(
+    ("34he" "\\(^{3}\\)He-\\(^{4}\\)He" nil :count 1)
+    ("3he" "\\(^{3}\\)He" nil :count 1)
+    ("4he" "\\(^{4}\\)He" nil :count 1)
+   ))
+