Question: Who was born in 1899 and wrote the book series "Mary Poppins"?

Context paragraphs:
Zizi Strallen: Zizi Strallen, born Sylphide Charity Vaigncourt-Strallen, is a British actress best known for playing Mary Poppins in the Cameron Mackintosh theatrical production of "Mary Poppins".

Charlotte's Web (1973 film): Charlotte's Web is a 1973 American animated musical drama film produced by Hanna-Barbera Productions and Sagittarius Productions and based upon the 1952 children's book of the same name by E. B. White.  The film, like the book, is about a pig named Wilbur who befriends an intelligent spider named Charlotte who saves him from being slaughtered.  Released to theaters by Paramount Pictures, "Charlotte's Web" features a song score of music and lyrics written by the Sherman Brothers, who had previously written music for family films like "Mary Poppins" (1964), "The Jungle Book" (1967), and "Chitty Chitty Bang Bang" (1968).  It is the first of only three Hanna-Barbera features not to be based upon one of their famous television cartoons, "Heidi's Song" (1982) and "Once Upon a Forest" (1993) being the other two.

P. L. Travers: Pamela Lyndon Travers, OBE ( ; born Helen Lyndon Goff; 9 August 1899 – 23 April 1996) was an Australian-born writer who spent most of her career in England.  She is best known for the "Mary Poppins" series of children's books, which feature the magical nanny Mary Poppins.

Mary Poppins (film): Mary Poppins is a 1964 American musical-fantasy film directed by Robert Stevenson and produced by Walt Disney, with songs written and composed by the Sherman Brothers.  The screenplay is by Bill Walsh and Don DaGradi, loosely based on P. L. Travers' book series "Mary Poppins".  The film, which combines live-action and animation, stars Julie Andrews in the role of Mary Poppins who visits a dysfunctional family in London and employs her unique brand of lifestyle to improve the family's dynamic.  Dick Van Dyke, David Tomlinson, and Glynis Johns are featured in supporting roles.  The film was shot entirely at the Walt Disney Studios in Burbank, California using painted London background scenes.

Mary Poppins Opens the Door: Mary Poppins Opens the Door is a British children's fantasy novel by the Australian-British writer P.L. Travers, the third book and last novel in the "Mary Poppins" series that features the magical English nanny Mary Poppins.  It was published in 1943 by Harcourt, Brace & World, Inc and illustrated by Mary Shepard and Agnes Sims.

The Sword in the Stone (film): The Sword in the Stone is a 1963 American animated musical fantasy comedy film produced by Walt Disney and released by Buena Vista Distribution.  The 18th Disney animated feature film, it was the final Disney animated film to be released before Walt Disney's death.  The songs in the film were written and composed by the Sherman Brothers, who later wrote music for other Disney films like "Mary Poppins" (1964), "The Jungle Book" (1967), "The Aristocats" (1970), and "Bedknobs and Broomsticks" (1971).

Mary Poppins, Goodbye: Mary Poppins, Goodbye (Russian: Мэри Поппинс, до свидания!  ; translit.  "Meri Poppins, do svidaniya") is a Soviet 1983 two-part musical miniseries (part 1 "Lady Perfection", part 2 "Week ends on Wednesday"), directed by Leonid Kvinikhidze.  It is loosely based on Mary Poppins stories by P. L. Travers.  The TV series were ordered by the Gosteleradio of USSR and produced by Mosfilm.  The official television premiere was on January 8, 1984.

Op zoek naar Mary Poppins: Op zoek naar Mary Poppins ("Looking for Mary Poppins") was a 2009 talent show-themed television series produced by the AVRO in the Netherlands and broadcast on AVRO.

Mary Poppins: Mary Poppins is a series of eight children's books written by P. L. Travers and published over the period 1934 to 1988.  Mary Shepard was the illustrator throughout the series.

Karen Dotrice: Karen Dotrice ( ; born 9 November 1955) is a British actress, known primarily for her role as Jane Banks in Walt Disney's feature film adaptation of the "Mary Poppins" book series.  Dotrice was born in Guernsey to two accomplished stage actors.  Her career began on stage, and expanded into film and television, including starring roles as a young girl whose beloved cat magically reappears in Disney's "The Three Lives of Thomasina" and with "Thomasina" co-star Matthew Garber as one of two children pining for their parents' attentions in "Poppins".  She appeared in five television programmes between 1972 and 1978, when she made her only feature film as an adult.  Her life as an actress concluded with a short run as Desdemona in the 1981 pre-Broadway production of "Othello".

Supporting paragraphs: Mary Poppins (film) P. L. Travers
Answer: P. L. Travers