question: When did Rębała and colleagues studied several Slavic populations with the aim of localizing the Proto-Slavic homeland ?
answer: 2007
turker_answer: Rębała and colleagues studied several Slavic populations with the aim of localizing the Proto-Slavic homeland in 2007 .
rule-based: Rębała and colleagues studied several Slavic populations with the aim of localizing the Proto-Slavic homeland in 2007 .