<documentation>The test is done by calculation on the first 12 digits and compare the result with the checksum number at the end. You have to pass a 13 digits number.</documentation>
<inputmessage="tns:IsValidISBN13SoapRequest"/>
<outputmessage="tns:IsValidISBN13SoapResponse"/>
</operation>
<operationname="IsValidISBN10">
<documentation>The test is done by calculation on the first 9 digits and compare the result with the checksum number at the end. You have to pass a 10 digits number or 8 digits and an X.</documentation>