1999, Frederick Barthelme, Steve Barthelme, Double down: reflections on gambling and loss, Houghton Mifflin Harcourt, →ISBN, page 66:
He'd bet three thousand and double down to six thousand, all of it hanging on the turn of the next card.
2005, Steve Bourie, American Casino Guide, Casino Vacations Press, →ISBN, page 92:
When deciding how to play your hand there are also three other options available to you besides standing or hitting. The first is called doubling down and most casinos will allow a player to double their bet on their first two cards and draw only one more card.
2005, Mike Turner, Bootlegger's 200 proof blackjack, Square One Publishers, →ISBN, page 32:
He then placed an additional $400 in the betting square to double down on the hard 14 the dealer had dealt him. He promptly busted and lost $800.
Hillary Clinton, John Edwards and Barack Obama all want to get out of Iraq. They all want to double down in Afghanistan.
2009, Alford Fowler, Double Down Blackjack: The Uncomplicated Version, manna hut, →ISBN, page 32:
It is important to remember that when a player opts to double down that the player is one; required to double the initial bet and two; is only dealt one additional card for better or for worse and loses the option to further hit or stand.
2009, Alford Fowler, Double Down Blackjack: The Uncomplicated Version[1], manna hut, →ISBN, page 44:
To indicate the desire to double down or split a pair, slide an amount of chips equal to the original bet into your betting circle.
2005, Steve Bourie, American Casino Guide, Casino Vacations Press, →ISBN, page 95:
When your cards total 11 you would always want to hit it because you can't bust, but before you ask for a card you should consider making a double down bet.
1987, Lance Humble, Carl Cooper, The World Greatest Blackjack Book[3], Doubleday, →ISBN, page 33:
The basic double-down play means that you may make a second wager no higher than the amount of your original bet and receive one and only one additional card.
2005, Steve Bourie, American Casino Guide, Casino Vacations Press, →ISBN, page 7:
This is your best casino game, but you must learn how to play your hands (when to hit, stand, double-down, split, etc.)
2005, Mike Turner, Bootlegger's 200 proof blackjack, Square One Publishers, →ISBN, page 3:
He knows to handle double-down opportunities and what to do with hands that should be split.