“Christmas is never over, unless you want it to be… Christmas is a state of mind.”

On Christmas http://books.google.com/books?id=TXDGeEkIN6oC&q=%22There+are+some+people+who+want+to+throw+their+arms+round+you+simply+because+it+is+Christmas+there+are+other+people+who+want+to+strangle+you+simply+because+it+is+Christmas%22&pg=PA85#v=onepage, The Book of This and That (1915)

"For the Other 365 Days", in Trans-communicator, Volume 44 (1927), p. 177.

Source: I'm a Stranger Here Myself: Notes on Returning to America after Twenty Years Away

Whoops! It's Christmas (1959)

Original: (it) È Natale ogni volta che sorridi a un bimbo, tenendogli la mano. È Natale ogni volta che riconosci i tuoi limiti, i tuoi errori. È Natale ogni volta che rimani in silenzio per ascoltare l'altro. È Natale ogni volta che doni con amore la tua dolcezza. È​ Natale ogni volta che ascolti la canzone del cuore.
Source: prevale.net

interviewed regarding American Atheists' Jersey City, New Jersey "You Know It's a Myth" billboard.

Source: Little Women (1868), Ch. 1 : Playing Pilgrims, First lines
Context: "Christmas won't be Christmas without any presents," grumbled Jo, lying on the rug.
"It's so dreadful to be poor!" sighed Meg, looking down at her old dress.
"I don't think it's fair for some girls to have plenty of pretty things, and other girls nothing at all," added little Amy, with an injured sniff.
"We've got Father and Mother, and each other," said Beth contentedly from her corner.
The four young faces on which the firelight shone brightened at the cheerful words, but darkened again as Jo said sadly, "We haven't got Father, and shall not have him for a long time." She didn't say "perhaps never," but each silently added it, thinking of Father far away, where the fighting was.

Simon (1956) quoted on CMU Libraries: Problem Solving Research http://shelf1.library.cmu.edu/IMLS/MindModels/problemsolving.html
1940s-1950s