1. Education for Sustainable Development Goals: Learning Objectiveshttp://unesdoc.unesco.org/images/0024/002474/247444e.pdf
2. IUCN Red Listhttp://cmsdocs.s3.amazonaws.com/summarystats/2017-3_Summary_Stats_Page_Documents/2017_3_RL_Stats_Table_1.pdf
3. Fostering empathy with wildlife: Factors affecting free-choice learning for conservation concern and behavior;Myers,2009
4. Venturing beyond the tyranny of small differences: The animal protection movement, conservation, and environmental education;Waldau,2013