ISBN — International Standard Book Number. The ISBN consists of 13 digits and uniquely identifies a book. The ISBN is unique and is necessary for the automated processing of information about the book in libraries and archives, as well as for the distribution of the book in retail networks.
Knowing this number publishers, booksellers, librarians, researchers can easily find any publication registered in this way, legally distribute it, control its sales, make an order for printing of books and additional printings. The ISBN number can be given to books and other kinds of publications.
The publications having ISBN number are registered in ISBN International Agency, and the information about such publications is published in International index of publishing houses and publishing organizations.
For periodicals there is also a similar standard — ISSN (International Standard Serial Number).

The cost of obtaining an ISBN number
Dear customers, please note that 16 books from the circulation are transferred to the Latvian Book Chamber, including those made by digital book printing.
UDC- Universal Decimal Classification — information classification system, widely used all over the world to systematize works of science, literature and art, periodicals, various types of documents and organize card catalogues, regardless of whether hardcover book printing have been printed or not.
LBC — Library-bibliographic classification. The worksheets are intended for organizing library collections, systematic catalogs, and card catalogs
Author’s mark— one of the main elements of the output information of a printed publication, introduced by the famous librarian Lyubov Borisovna Khavkina in 1916. Sometimes incorrectly called «Ketter’s sign». It consists of a letter and two digits. The letter is the first letter of the author’s last name or the title of the book. The numbers are determined by special tables in which a two-digit number is associated with each sequence of the first few letters of the author’s surname or the title of the book (if the authors of the book are more than three people, or there are no authors).
Cost of assignment of ISBN, UDC/LBC and author’s mark codes — 300 euros.