Sept 1 (Reuters) - Online gambling firm 888 Holdings stepped up a billion pound battle for Bwin.party Digital Entertainment on Tuesday, submitting a revised takeover proposal as it looks to see off rival interest from GVC Holdings (Other OTC: GMVHF - news ) .
Analyze the relationship between '888 Holdings' and 'gambling' within the context of the input sentence.
Options: owner of, location of formation, distributed by, industry