B. MERIT and G. LEMARQUAND, “Ironless Lowfrequency Loudspeaker Working Under its Resonance Frequency”, Arch. Acoust., vol. 33, no. 4(S), pp. 59–64, Dec. 2008, Accessed: Jan. 18, 2026. [Online]. Available: https://acoustics.ippt.gov.pl/index.php/aa/article/view/836