Supriyati, Hikmah. 2021. “The Role of the Ngunduh Tradition in the Conservation of Swallow’s Nests in Karangbolong Village, Kebumen Regency of Central Java, Indonesia”. Proceeding International Conference on Science and Engineering 4 (March):390-93. http://sunankalijaga.org/prosiding/index.php/icse/article/view/695.