Table schema:
CREATE TABLE table_27877656_7 (surface VARCHAR, score VARCHAR, edition VARCHAR)

Question: For edition is 2011 europe/africa group iiib and surface where score is 6–4, 6–1 please specify all the surface
SQL: SELECT surface FROM table_27877656_7 WHERE score = "6–4, 6–1" AND edition = "2011 Europe/Africa Group IIIB"