9.Ref:High Level Language Trend - nob-suz/crystal GitHub Wiki

Erik Michaels-Ober at RubyConf　Australia(2015/Feb)

Towards a Higher-Level Language https://rubyconf.eventer.com/rubyconf-australia-2015-1223/towards-a-higher-level-language-by-erik-michaels-ober-1746

Tour of language landscape Yan Cui
http://www.slideshare.net/theburningmonk/tour-of-language-landscape