found: Sachs, C. The history of musical instruments, 1940:p. 166 (hsüan, globular flute in Shang dynasty; probably used as a voice mask in a religious rite)
found: Mathews' Chinese-English dict.(hsüan, ancient wind instrument, shaped like an egg, made of porcelain)
found: Marcuse, S. Musical instruments(hsüan)
found: Grove Music Online, WWW site, November 19, 2009(Globular flute employed in Han Chinese Confucian rituals. The xun (pronounced 'hsün') is an egg-shaped flute of baked clay, with a blow-hole at its apex and usually between three and eight finger-holes distributed in various patterns. Sizes vary between about 8 and 13 cm in height. Because of its globular wind chamber, the xun has a range of only about one octave, without usable overtones)