Douglas, Carstairs (1873) “jio̍k”, in Chinese-English Dictionary of the Vernacular or Spoken Language of Amoy, [With 1923 Supplement after the Appendix by Thomas Barclay, Shanghai: Commercial Press, Ltd.] edition (overall work in Hokkien and English), London: Trübner & Co., page 183; New Edition (With Chinese Character Glosses) edition, London: Presbyterian Church of England, 1899, page 183
Duffus, William (1883) “mattress”, in English-Chinese Vocabulary of the Vernacular or Spoken Language of Swatow, Swatow: English Presbyterian Mission Press, page 175