Satake, Kenichi; Oyagi, Akira (1995). "Natural acidification of lakes and rivers in Japan: The ecosystem of Lake Usoriko (ph 3.4–3.8)". Water, Air, & Soil Pollution. 85 (2): 511–516. Bibcode:1995WASP...85..511S. doi:10.1007/BF00476880.
Satake, Kenichi; Oyagi, Akira (1995). "Natural acidification of lakes and rivers in Japan: The ecosystem of Lake Usoriko (ph 3.4–3.8)". Water, Air, & Soil Pollution. 85 (2): 511–516. Bibcode:1995WASP...85..511S. doi:10.1007/BF00476880.