src/Isbn.php
public function getPublisherIdentifier() : string
    {
        if ($this->rangeInfo === null) {
            throw IsbnException::unknownGroup($this->isbn);
        }

        if ($this->rangeInfo->parts === null) {
            throw IsbnException::unknownRange($this->isbn);
        }

        return $this->rangeInfo->parts[$this->is13 ? 2 : 1];
    }
public function getPublisherIdentifier() : string
    {
        if ($this->rangeInfo === null) {
            throw IsbnException::unknownGroup($this->isbn);
        }

        if ($this->rangeInfo->parts === null) {
            throw IsbnException::unknownRange($this->isbn);
        }

        return $this->rangeInfo->parts[$this->is13 ? 2 : 1];
    }
public function getPublisherIdentifier ( ) : string { if ( $ this -> rangeInfo === null ) { throw IsbnException :: unknownGroup ( $ this -> isbn ) ; } if ( $ this -> rangeInfo -> parts === null ) { throw IsbnException :: unknownRange ( $ this -> isbn ) ; } return $ this -> rangeInfo -> parts [ $ this -> is13 ? 2 : 1 ] ; }
Returns the publisher identifier.

The publisher identifier identifies a particular publisher within a group.

@return string

@throws IsbnException If this ISBN is not in a recognized group or range.
Returns the publisher identifier .