Need help with network_query_posts.

Would just like some assistance with network_query_posts. I'm trying to limit it by excluding certain roles or authors but can't get the syntax right. So this works 'author' => -82, but if I want to exclude multiple authors this is not working 'author__not_in' => array(82) or 'author' => '-2, -3, -4', //excludes users with id 2, 3 and 4.

Please help.