Each country has an issuing authority - a web search should reveal who that is in your country. ISBN's are usually issued in blocks, rather than singularly, usually tens. Part of each one is a code for the publisher, which can be anyone (at least in the UK).
The ISBN of The Code of the Woosters is 1841591009.
The ISBN of The Code of Romulus is 9781842555804.
The ISBN of Code of the Clans is 978-0061660092.
The ISBN of The Code Book is 978-1857028799.
The ISBN of The AdSense Code is 978-1933596709.
The ISBN of Code Noir - novel - is 1841492574.
The ISBN of The Da Vinci Code by Dan Brown is 978-0307474278.
The ISBN of Code to Zero is 0-333-78076-0.
The ISBN of The Bar Code Rebellion is 978-0439803854.
The ISBN of The Bar Code Tattoo is 978-0439395625.
The ISBN of Catalyst Code is 978-1-4221-0199-5.
The ISBN of The Asti Spumante Code is 0-7515-3768-3.