Barter has always been a feature of the Soviet Union 's foreign trade , but Yeltsin 's decrees liberalising foreign trade in 1991-1992 has given barter a new impetus .
<response> Barter has always been a feature of the <location>Soviet Union</location> 's foreign trade , but <person>Yeltsin</person> 's decrees liberalising foreign trade in 1991-1992 has given barter a new impetus . </response>