Editing Pigpen cipher (section)

==References==
* {{cite book|title=The History of Codes and Ciphers in the United States(USA) Prior to World War I|editor=Barker, Wayne G.|year=1978|publisher=[[Aegean Park Press]]|isbn=0-89412-026-3}}
* {{cite book|author=Gardner, Martin|author-link=Martin Gardner|title=Codes, ciphers and secret writing|year=1972|publisher=Courier Corporation |isbn=0-486-24761-9|url-access=registration|url=https://archive.org/details/codescipherssecr00gard_0}}
* {{cite book|author=Kahn, David|author-link=David Kahn (writer)|title=The Codebreakers. The Story of Secret Writing|publisher=Macmillan|year=1967}}
* {{cite book|author=Kahn, David|author-link=David Kahn (writer)|title=The Codebreakers. The Story of Secret Writing|publisher=[[Charles Scribner's Sons|Scribner]]|year=1996|isbn=0-684-83130-9}}
* {{cite book|author=Newton, David E.|chapter=Freemason's Cipher|title=Encyclopedia of Cryptology|url=https://archive.org/details/encyclopediaofcr0000newt|url-access=registration|year=1998|publisher=Bloomsbury Academic |isbn=0-87436-772-7}}
* {{cite book|author=Pratt, Fletcher|title=Secret and Urgent: The story of codes and ciphers|year=1939|isbn=0-89412-261-4|publisher=[[Aegean Park Press]]}}
*{{cite book|title=A glossary of cryptography|author1=Shulman, David |author2=Weintraub, Joseph |year=1961|publisher=Crypto Press|pages=44}}
* {{cite book|title=Codes, Ciphers, and other Cryptic & Clandestine Communication|author=Wrixon, Fred B.|isbn=1-57912-040-7|year=1998|publisher=Black Dog & Leventhal Publishers, Inc.}}