Extra metadata for Book Information

pressbooks-google-scholar.php

<?php

function pb_gs_add_meta_boxes() {
	x_add_metadata_group( 'google-scholar-metadata', 'metadata', array(
	'label' => __( 'Google Scholar Metadata', 'pressbooks-google-scholar' )
	) );

	x_add_metadata_field( 'citation_title', 'metadata', array(
		'group' => 'google-scholar-metadata',
		'label' => __( 'Citation Title', 'pressbooks-google-scholar' )
	) );

	x_add_metadata_field( 'citation_author', 'metadata', array(
		'group' => 'google-scholar-metadata',
		'label' => __( 'Citation Author', 'pressbooks-google-scholar' )
	) );

	x_add_metadata_field( 'citation_publication_date', 'metadata', array(
		'field_type' => 'datepicker',
		'group' => 'google-scholar-metadata',
		'label' => __( 'Citation Publication Date', 'pressbooks-google-scholar' )
	) );
}

add_action( 'custom_metadata_manager_init_metadata', 'pb_gs_add_meta_boxes' );