TIMSS 2015 international results in mathematics
Mullis, Ina V. S., Michael O. Martin, Pierre Foy, and Martin Hooper. “TIMSS 2015 international results in mathematics”, Chestnut Hill, Mass.: TIMSS & PIRLS International Study Center, Lynch School of Education, Boston College, 2016. http://hdl.handle.net/2345/bc-ir:109275.