XML query results and errors

Query results may be requested in 3 different formats:

UNIXSD is the recommended and most robust format, but XSD_XML is the default for many services for legacy reasons.

Errors

Possible errors returned by malformed or insufficient queries include:

an invalid XML query will return no result (<body/>)
Either first page or author must be supplied.
Either ISSN or Journal title must be supplied.
unreasonable DOI found
* an 'unreasonable DOI' does not follow the expected DOI format (10.XXXX/yyy..) and/or exceeds 200 characters.
Piped Query must contain either 9 (for journals) or 11 (for books/conference proceedings) pipes.
Either ISSN/ISBN or Series/Volume title must be supplied.