Where the ISBN barcode of a book cannot be found on the website of the State Administration of Press, Publication, Radio, Film and Television or the China Press and Publication Information Network, the ISBN of the book is a false ISBN. This book is pirated or fake. Because books published regularly at ordinary times must have ISBN barcodes.

You can log on to the website of the State Administration of Press, Publication, Radio, Film and Television or China Press and Publication Information Network, select the publication query function, and enter the ISBN number or CIP number to search whether it is a genuine publication.

Extended data:

Inspection method

According to ISO-2 108, the parity bit generation is calculated by the coefficient 1 1. The calculation method is to multiply the first nine digits of ISBN by numbers from 10 to 2 in turn, add the products, and divide the sum by11; If there is no remainder, the check number is "0"; If there is a remainder, subtract it from 1 1 and the difference is the check number. If the difference is 10, it is represented by an "x" representing the Roman numeral 10.

ISBN is used in textbooks, printed matter, micro-reproduction, educational television or movies, mixed media publications, microcomputer software, atlases and maps, Braille publications and electronic publications.

Baidu encyclopedia-international standard book number