Sources:
Estonia:
http://education.stateuniversity.com/pages/447/Estonia-EDUCATIONAL-SYSTEM-OVERVIEW.html
https://www.hm.ee/et/tegevused/koolivaheajad
Finland:
https://www.utu.fi/en/units/tis/calendar/Pages/home.aspx
https://fillingmymap.com/2015/04/15/11-ways-finlands-education-system-shows-us-that-less-is-more/
Germany:
https://www.angloinfo.com/how-to/germany/family/schooling-education/school-schedule
https://www.howtogermany.com/pages/germanschools.html
https://www.schulferien.org/deutschland/ferien/2017-2018/
https://publicholidays.de/school-holidays/berlin/
Hong Kong:
http://www.edb.gov.hk/en/edu-system/primary-secondary/applicable-to-primary/whole-day-schooling/index.html
http://www.edb.gov.hk/attachment/en/curriculum-development/resource-support/guidelines-sch-calendar/Calculation%20of%20School%20Holidays%20and%20School%20Days%20-%20June%202011.pdf
Japan:
http://web-japan.org/kidsweb/explore/calendar/april/schoolyear.html
http://global.chuo-u.ac.jp/english/unicms/wp-content/uploads/2014/03/Academic_Year_and_Academic_Calendar.pdf
New Zealand:
https://parents.education.govt.nz/essential-information/school-terms-and-holidays/
https://www.newzealandnow.govt.nz/living-in-nz/education/school-system
Netherlands:
https://study.studentnews.eu/s/3693/75527-School-year-in-Europe/4468142-Netherlands-201718.htm
https://www.government.nl/topics/school-holidays/question-and-answer/school-holidays-2017%E2%80%932018
Ontario:
http://www.tdsb.on.ca/About-Us/Calendar
https://settlement.org/ontario/education/elementary-and-secondary-school/general-information/when-do-children-begin-and-end-school-each-day/
Shanghai:
http://xiaoxue.eol.cn/zx/shanghai/xiaoxue/201707/t20170717_1541162.shtml
https://www.timeanddate.com/holidays/china/2017
http://hechingered.org/content/a-day-in-the-life-of-chinese-students_3826/
Singapore:
https://www.moe.gov.sg/news/press-releases/school-terms-and-holidays-for-2018
https://www.angloinfo.com/how-to/singapore/moving/country-file/public-holidays
https://internationalednews.com/2014/09/17/the-school-day-singapore/
South Korea:
http://www.bbc.com/news/education-25187993
http://www.jobmonkey.com/asia/school_calendar_in_s_k_/
Taiwan:
https://www.angloinfo.com/how-to/taiwan/family/schooling-education/school-year
http://www.jobmonkey.com/asia/school_calendar_in_tw/
USA
https://nces.ed.gov/surveys/pss/tables/table_2004_06.asp
https://nces.ed.gov/surveys/pss/tables/table_2004_06.asp
