Form 10-Q_June 30, 2018
XBRL Files To download, simply click the link to display the source page, and then right-click and Save As. Description Document XBRL INSTANCE DOCUMENT zgsi-20180630.xml XBRL TAXONOMY EXTENSION SCHEMA zgsi-20180630.xsd XBRL TAXONOMY EXTENSION CALCULATION LINKBASE zgsi-20180630_cal.xml XBRL TAXONOMY EXTENSION DEFINITION LINKBASE zgsi-20180630_def.xml XBRL TAXONOMY EXTENSION LABEL LINKBASE zgsi-20180630_lab.xml XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE zgsi-20180630_pre.xml