References:

Design and Experimental Results for the S809Airfoil. Dan M. Somers, NREL/SR-440-6918, UC Category: 1213, DE97000206

Vortex Shedding Lock-In due to Pitching Oscillation of a Wind Turbine Blade Section at High Angles of Attack. Craig Meskell and Alberto Pellegrino, International Journal of Aerospace Engineering, Volume 2019, Article ID 6919505, 12 pages, https://doi.org/10.1155/2019/6919505