Reference / Source: (1) It is narrated in Abu Zur'ah al-Dimashqi's "Tarikh" (p. 218), and in Ibn 'Asakir's "Tarikh Dimashq" (25/486, 491) through two routes from Abu Mushir.
Technical note / Defect ('illah): But it does not mention the year (of death).

Reference / Source: In "Tarikh Abi Zur'ah al-Dimashqi" (p. 218, 688-689), and through his route 'Abd al-Jabbar al-Khawlani in "Tarikh Darayya" (p. 114), and Ibn 'Asakir (25/488) narrated through the route of Muhammad bin 'A'idh, from Abu Mushir, that he said: "I read in the book of Yazid bin 'Ubaydah that Abu 'Ubaydah died in the year 17 AH."

Important point: We say: it seems that this is the more firmly established report from Abu Mushir about the year of Abu 'Ubaydah's death; and Allah knows best.
Technical note / Defect ('illah): And Ibn 'A'idh is alone in this, as al-Dhahabi said in "al-Siyar" (1/23).

General principle: The majority of historians hold that he died in the year 18 AH, as Ibn 'Abd al-Barr said in "al-Tamhid" (2/277).

Reference / Source: For confirmation of his statement, see "Tarikh Dimashq" (25/488) and what follows it.