• Model for the formation of "optimal" vortex rings with taking into account viscosity [Electronic resource]Kaplanski, Felix; Rudi, ÜloProceedings of the 21st IUTAM Congress : Warsaw, Poland2005 / p. FM25 [CD-ROM] https://www.researchgate.net/publication/278242738_A_model_for_the_formation_of_optimal_vortex_rings_with_taking_into_account_viscosity