[1] ECMAScript Language Specification ECMA-262 6th Edition – DRAFT ( (2014-04-28 18:21:11 +09:00 版)) https://people.mozilla.org/~jorendorff/es6-draft.html#sec-date.prototype.toisostring

[2] Date.prototype.toISOString() - JavaScript | MDN (2017-05-20 21:36:38 +09:00) https://developer.mozilla.org/nl/docs/Web/JavaScript/Reference/Global_Objects/Date/toISOString