The Wizard of Oz

The Wizard of Oz is the common name for The Wonderful Wizard of Oz, a children's book by L. Frank Baum, published on Earth in 1900. It is also the title of a 1939 movie adaptation of the book.

In 2151, Commander Trip Tucker compared the capital city of the planet Coridan to the Emerald City, a location from the book. 

If I Only Had a Heart, a tune that Doctor Ira Graves used to whistle, is a song from the 1939 movie adaptation of the book, sung by the character of the "Tin Man". Graves also compared Data's desire to become more human to the Tin Man's quest for a heart. 

Starfleet scientists dubbed Gomtuu "Tin Man" after one of the characters in The Wizard of Oz. 

When Doctor Beverly Crusher was caught in a shrinking warp bubble and began to realize how easy it would be to leave the bubble, she said "Click my heels together three times and I'm back in Kansas?", referencing a phrase from The Wizard of Oz, spoken by the main character, Dorothy. 

The Clown quoted The Wizard of Oz from Harry Kim's memory, stating "There is no place like home" and mocked the Ensign because he was restrained and thus not able to "click his heels together three times". 

In 2373, Jake Sisko and Nog said "Lions, Gigers, bears...", "Oh my", paraphrasing the line "Lions and tigers and bears, oh my" from the film version of The Wizard of Oz. 

Background
Billy Curtis, who had a non-speaking role as one of the "small copper-skinned ambassadors" in, played a small part as one of the Munchkins in The Wizard of Oz.

In, Armus called Data Tin Man. It is not clear however if he had derived the term from The Wizard of Oz, as it would appear unlikely he had knowledge of the book.

Jean-Luc Picard's line to Lily Sloane in about not being in Montana any more is an obvious reference to line in The Wizard of Oz about not being in Kansas anymore.

The Wizard of Oz is one of the few real-life movies referenced in Star Trek not produced by Paramount Pictures.