Tham khảo Phơi nhiễm âm thanh

  1. ↑ "Letter symbols to be used in electrical technology – Part 3: Logarithmic and related quantities, and their units", IEC 60027-3 Ed. 3.0, International Electrotechnical Commission, ngày 19 tháng 7 năm 2002.
  2. ↑ Ross Roeser, Michael Valente, Audiology: Diagnosis (Thieme 2007), p. 240.
  3. ↑ Thompson, A. and Taylor, B. N. sec 8.7, "Logarithmic quantities and units: level, neper, bel", Guide for the Use of the International System of Units (SI) 2008 Edition, NIST Special Publication 811, 2nd printing (November 2008), SP811 PDF