Given the input sentence, please extract the subject and object containing a certain relation in the sentence according to the following relation types, in the format of "relation1: word1, word2; relation2: word3, word4". Relations include: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

Volkswagen AG's Chief Executive Officer Martin Winterkorn poses for media during the annual shareholder meeting of Volkswagen AG in Hamburg, Germany, in this April 23, 2009 file photo.

Answer: position_held: Martin Winterkorn, Chief Executive Officer