Gadomski, Adam, and Janusz Cyran. “Note on Appearance of Zigzak Type Self Similarity in Flying Bird Flocks Performing Directional Collective Motions in Mild-Weather Conditions”. Current Topics in Biophysics, vol. 41, no. 1, Dec. 2018, pp. 5-9, doi:10.2478/ctb-2018-0001.