{"id":"webster2018background","DOI":"10.1126/science.aaq0131","URL":"https://doi.org/10.1126/science.aaq0131","type":"article-journal","title":"Background levels of methane in Mars' atmosphere show strong seasonal variations","author":[{"given":"Christopher R.","family":"Webster"},{"given":"Paul R.","family":"Mahaffy"},{"given":"Sushil K.","family":"Atreya"},{"given":"John E.","family":"Moores"},{"literal":"et al."}],"issued":{"date-parts":[[2018]]},"year-text":"2018","container-title":"Science 360(6393), 1093–1096","catalog-key":"SRC0D7EXME03TED"}