ISBN

Publisher	Digits
Addison-Wesley	0-201
Amer. Math. Soc.	0-821
Birkhäuser Basel	3-7643
Birkhäuser Boston	0-8176
Cambridge University Press	0-521
CRC Press	0-8493
Dover	0-486
McGraw-Hill	0-070
Oxford University Press	0-198
Springer-Verlag Berlin	3-540
Springer-Verlag New York	0-387
Tarquin Publications	0-906212
Wiley	0-471

The International Standard Book Number (ISBN) is a 10-digit Code which is used to uniquely identify a book. The digits $d_i$ are arranged in four groups. The first group is a single digit which codes country or language in which a publisher is incorporated: 0 for English, 2 for French, 3 for German, etc. The next group of digits specifies the publisher, and may range in length from two to seven digits, with fewer digits used for larger publishers. The third group of digits specifies an individual book, and may be from one to six digits in length. The last digit $d_{10}$ is a check digit which may be in the range 0-9 or X (where X is the Roman Numeral for 10). The check digit is computed from the equation

$$10d_1+9d_2+8d_3+\ldots+2d_9+d_{10}\equiv 0\ \left({{\rm mod\ } {11}}\right).$$

For example, the number for this book is 0-8493-9640-9, and

$10\cdot 0+9\cdot 8+8\cdot 4+7\cdot 9+6\cdot 3+5\cdot 9$
$+4\cdot 6+3\cdot 4+2\cdot 0+1\cdot 9=275=25\cdot 11\equiv 0{\rm\ (mod\ }11),$

as required.

References

Hill, R. First Course in Coding Theory. Oxford, England: Oxford University Press, 1986.