Utilize the input text as a context reference, choose the right relationship between DESFA and gas from the options. Options: 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.

-- SOCAR, Azerbaijan's state energy company, to buy stakes in Greek natural gas grid operator DESFA from Greek natural gas utility DEPA (notified Oct (HKSE: 3366-OL.HK - news ) .

Answer: product_or_material_produced