John Batchelor (1905) An Ainu-English-Japanese dictionary (including a grammar of the Ainu language)[1], Tokyo; London: Methodist Publishing House; Kegan Paul, Trench, Trubner Co., page 133, available online here
The katakana syllable フ(fu). Its equivalent in hiragana is ふ(fu). It is the twenty-eighth syllable in the gojūon order; its position is ハ行ウ段(ha-gyō u-dan, “row ha, section u”).
Unlike the hiragana system, used for Japanese language words that kanji does not cover, the katakana syllabary is used primarily for transcription of foreign language words into Japanese and the writing of loan words (collectively gairaigo), as well as to represent onomatopoeias, technical and scientific terms, and the names of plants, animals, and minerals. It is also occasionally used colloquially in some words for emphasis. Names of Japanese companies, as well as certain Japanese language words, are also sometimes written in katakana rather than the other systems. Formerly, female given names were written in katakana. [edit]