Nicolas Bourbaki is the pseudonym of a group of mostly French-connected mathematicians attempting to expose the field in an axiomatic and self-contained, encyclopedic form. Concealment of identity A pseudonym may be used to protect the writer of exposé books about espionage or crime. Former SAS soldier Steven Billy Mitchell used the pseudonym Andy McNab for his book about a failed SAS mission titled Bravo Two Zero. The name Ibn Warraq ("son of a papermaker") has been used by dissident Muslim authors. Author Brian O'Nolan used the pen names Flann O'Brien and Myles na gCopaleen for his novels and journalistic writing from the 1940s to the 1960s because Irish civil servants were not permitted at that time to publish political writings. The identity of the enigmatic twentieth-century novelist B. Traven has never been conclusively revealed, despite thorough research. A multiple-use name or anonymity pseudonym is a pseudonym open for anyone to use and these have been adopted by various groups, often as a protest against the cult of individual creators. In Italy, two anonymous groups of writers have gained some popularity with the collective names of Luther Blissett and Wu Ming. Eastern literature India In Indian languages, writers may put a pen name at the end of their names, like Ramdhari Singh Dinkar. Some writers, like Firaq Gorakhpuri, wrote only under a pen name. In early Indian literature, authors considered the use of names egotistical. Because names were avoided, it is difficult to trace the authorship of many earlier literary works from India. Later writers adopted the practice of using the name of their deity of worship or Guru's name as their pen name. In this case, typically the pen name would be included at the end of the prose or poetry. Composers of Indian classical music used pen names in compositions to assert authorship, including Sadarang, Gunarang (Fayyaz Ahmed Khan), Ada Rang (court musician of Muhammad Shah), Sabrang (Bade Ghulam Ali Khan), and Ramrang (Ramashreya Jha). Other compositions are apocryphally ascribed to composers with their pen names. Hong Kong Wuxia novelist Louis Cha uses the pen name Gum Yoong (金庸) by taking apart the components of the Chinese character in his given name (鏞) from his birth name Cha Leung-yung (查良鏞). Japan Japanese poets who write haiku often use a haigō (俳号). The haiku poet Matsuo Bashō had used two other haigō before he became fond of a banana plant