Kosta Rika: Lingkungan Bersih, Hidup Bahagia

[2] Global Metrics for the Environment, 2016 Report (www.epi.yale.edu)

[3] The Happy Planet Index 2016, New Economics Foundation (www.happyplanetindex.org)

[4] Human Development Report 2015, UNDP (hdr.undp.org)

Foto: fordneyfoundation.org