This possibility arises when the player has an ace (value 11) and another card having value 10 (10, king, queen, or jack).
http://www.prepody.ru/topic68671.html
https://neoternia.net/viewtopic.php?p=311642#p311642
https://bbs.digumao.cn/forum.php?mod=viewthread&tid=329&extra=
https://gravatar.com/noisily3938645bf8
http://biopharmamash.com/viewtopic.php?t=1251020
http://come4play.com/forum/viewtopic.php?t=13166
http://023002.com/forum.php?mod=viewthread&tid=1899840&extra=
http://oldsite.giessen46ers.de/fantalk/viewtopic.php?f=9&t=198924
http://treasureillustrated.com/showthread.php?tid=319979
http://881.cz/forum.php?mod=viewthread&tid=38011&extra=
https://neoternia.net/viewtopic.php?t=240941
http://881.cz/forum.php?mod=viewthread&tid=34404&extra=
https://forum.zweb-apps.xyz/viewtopic.php?t=3546
http://horsecity.ru/phpBB3/viewtopic.php?f=8&t=277866
https://www.seono1.co.th/forum/index.php/topic,1046125.new.html#new
https://talk.hyipinvest.net/threads/317943/