维基共享资源中相关的多媒体资源:秒 Official BIPM definition of the second (页面存档备份,存于互联网档案馆) Seconds and leap seconds by the USNO (页面存档备份,存于互联网档案馆) The leap second: its history and
was falling very fast – from 33,000 to 11,725 feet [10,058至3,574米] in 60 seconds t.co/f3Z8Gy10O5 (推文). 2016-01-08. (原始内容存档于2016-01-10) –通过Twitter. Hradecky