1. Hanyu J., Sakuratani T., Abe H., and Ishiguro T., 1973: Studies on promotion of snow melting in a grassland. Part 1. On the promotion of snow melting by the black powders. Res. Bull. Hokkaido Natl. Agric. Exp. Stn., 106, 19-36 (in Japanese with English summary).
2. Hasegawa M., Tanaka H., Hirota T., and Tadano T., 2007: Agricultural snowmelting agents. Japanese Patent. No.2007-330495, applying (in Japanese) (長谷川益男.田中弘康.広田知良.但野利秋,2007:融雪材,特願2007-330495).
3. Hokkaido Government, 2007: Source of archived data of amount of wastes of fish and shellfish in Hokkaido, 2005, available from ‹http://www.pref.hokkaido.lg.jp/sr/ssk/›, (accessed October 21, 2007) (北海道水産林務部水産振興課ホームページ).
4. Ishii Y., 1959: Studies on snowmelting Basic snow survey. Hokkaido Electric Power Company, Sapporo District Meteological Observatory, pp. 84 (in Japanese). (石井幸男,1959:融雪の研究,積雪基礎調査.北海道電力株式会社,札幌管区気象台,84pp.)
5. Muramatsu K., 1982: The promotion of snow melting in a cultivated land. Agriculture and Horticulture. 57, 1297-1300 (in Japanese). (村松謙生,1982:農耕地の融雪促進技術現状と問題点.農業および園芸,57,1297-1300.)