Fatal error: Uncaught Error: Call to a member function getId() on null in /home/eujour5/public_html/tmp/upgrade/ojs3320/lib/pkp/classes/publication/PKPPublication.inc.php:168 Stack trace: #0 /home/eujour5/public_html/tmp/upgrade/ojs3320/lib/pkp/classes/submission/PKPSubmission.inc.php(423): PKPPublication->getAuthorString(Array) #1 /home/eujour5/public_html/tmp/upgrade/ojs3320/cache/t_compile/e26d2de610226743d9feff244fb14ef53700227f^7cf1cd52b8ba8108de77f197078de34b733dd394_0.app.frontendobjectsarticle_summary.tpl.php(77): PKPSubmission->getAuthorString() #2 /home/eujour5/public_html/tmp/upgrade/ojs3320/lib/pkp/lib/vendor/smarty/smarty/libs/sysplugins/smarty_template_resource_base.php(123): content_679e79898fee20_05466292(Object(Smarty_Internal_Template)) #3 /home/eujour5/public_html/tmp/upgrade/ojs3320/lib/pkp/lib/vendor/smarty/smarty/libs/sysplugins/smarty_template_compiled.php(114): Smarty_Template_Resource_Base->getRenderedTemplateCode(Object(Smarty_Internal_Template)) #4 /home/eujour5/public_html/tmp/upgrade/ojs3320/l in /home/eujour5/public_html/tmp/upgrade/ojs3320/lib/pkp/classes/publication/PKPPublication.inc.php on line 168