Question: Which book is the third in the Oz Series, and is the one which introduces the character Billina? 

Context paragraphs:
Rinkitink in Oz: Rinkitink in Oz: Wherein is Recorded the Perilous Quest of Prince Inga of Pingaree and King Rinkitink in the Magical Isles that Lie Beyond the Borderland of Oz.  is the tenth book in the Land of Oz series written by L. Frank Baum.  Published on June 20, 1916, with full-color and black-and-white illustrations by artist John R. Neill, it is significant that no one from Oz appears in the book until its climax; this is due to Baum's having originally written most of the book as an original fantasy novel over ten years earlier, in 1905.  Most of the action takes place on three islands – Pingaree, Regos, and Coregos – and within the Nome King's caverns.  Since the original ruler of the nomes, Roquat – who later renamed himself Ruggedo, was deposed in 1914's "Tik-Tok of Oz", Baum had to cleverly rework the tale to accommodate his successor, the well-intentioned – but politically motivated – Kaliko.

Billina: Billina is a fictional character in the classic children's series of Oz books by American author L. Frank Baum.  She is first introduced in "Ozma of Oz" (1907).

Ozma of Oz: Ozma of Oz: A Record of Her Adventures with Dorothy Gale of Kansas, Billina the Yellow Hen, the Scarecrow, the Tin Woodman, Tik-Tok, the Cowardly Lion and the Hungry Tiger; Besides Other Good People Too Numerous to Mention Faithfully Recorded Herein published on July 30, 1907, was the third book of L. Frank Baum's Oz series.  It was the first in which Baum was clearly intending a series of Oz books.

Cap'n Bill: Cap'n Bill Weedles is a fictional character found in L. Frank Baum's Land of Oz.  Cap'n Bill and his friend Trot were introduced in Baum's fantasy novels "The Sea Fairies" (1911) and "Sky Island" (1912).  They first appear in Oz in "The Scarecrow of Oz" (1915), the ninth book in the Oz series.

Princess Ozma: Princess Ozma is a fictional character from the Land of Oz, created by L. Frank Baum.  She appears in every book of the Oz series except the first, "The Wonderful Wizard of Oz" (1900).

The Emerald City of Oz: The Emerald City of Oz is the sixth of L. Frank Baum's fourteen Land of Oz books.  It was also adapted into a Canadian animated film in 1987.  Originally published on July 20, 1910, it is the story of Dorothy Gale and her Uncle Henry and Aunt Em coming to live in Oz permanently.  While they are toured through the Quadling Country, the Nome King is assembling allies for an invasion of Oz.  This is the first time in the Oz series that Baum made use of double plots for one of the books.

The Runaway in Oz: The Runaway in Oz is an Oz book by long-time Oz illustrator John R. Neill.  It was written originally during 1943 and was meant to be the thirty-seventh book in the Oz series.  However, Neill died before he could edit or illustrate the book.  Oz publisher Reilly & Lee decided not to publish the book due to shortages caused by World War II.  The text remained a possession of Neill's family.

Glinda of Oz: Glinda of Oz is the fourteenth Land of Oz book written by children's author L. Frank Baum, published on July 10, 1920.  It is the last book of the original Oz series, which was later continued by other authors.  Like most of the Oz books, the plot features a journey through some of the remoter regions of Oz; though in this case the pattern is doubled: Dorothy and Ozma travel to stop a war between the Flatheads and Skeezers; then Glinda and a cohort of Dorothy's friends set out to rescue them.  The book was dedicated to Baum's second son, Robert Stanton Baum.

Oz Squad: Oz Squad is a comic book series using characters and setting from L. Frank Baum's Land of Oz series, "updated for a more adult audience."  It was created and written by Steve Ahlquist.  The premise is that Dorothy, the Scarecrow, the Tin Woodman and the Cowardly Lion are now part of "Gale Force" (Not to be confused with the "OzF5: Gale Force" (2005) comic by Alias Enterprises), a "" type organization working to protect Oz from all manner of bizarre threats.

Animal Fairy Tales: Animal Fairy Tales is a collection of short stories written by L. Frank Baum, the creator of the Land of Oz series of children's books.  The stories (animal tales, comparable to Aesop's Fables or the "Just-So Stories" and "Jungle Book" of Rudyard Kipling) first received magazine publication in 1905.  For several decades in the twentieth century, the collection was a "lost" book by Baum; it resurfaced when the International Wizard of Oz Club published the stories in one volume in 1969.

Supporting paragraphs: Billina Ozma of Oz
Answer: Ozma of Oz