Articles are stored together with all the other content objects in the table: ezcontentobject_ tables. The actual data can be found in the table ezcontentobject_attribute
import:
http://ez.no/ez_publish/documentation/incoming/setting_up_rss_import
export via admin->setup->RSS. http://ez.no/community/forum/setup_design/how_do_you_set_up_rss_exports
http://ez.no/content/advancedsearch?SearchText=rss+export&SearchDate=-1&SearchPageLimit=2&SearchContentClassID=14&SearchButton=Search
more help: http://ez.no/products/books/ez_publish_book