Antti J. Niemi
Urs Schreiber
Introducing what came to be called the Skyrme-Fadeev model and its Hopfion solitons:
Ludwig D. Faddeev: Quantization of Solitons, talk at ICHEP 76 (1975) [inSpire:2631]
Ludwig D. Faddeev, Antti J. Niemi: Stable knot-like structures in classical field theory (preprint title: Knots and Particles), Nature 387 (1997) 58–61 [arXiv:hep-th/9610193, doi:10.1038/387058a0]
and relation to the dual superconductor model of color confinement:
On anyonic vortices in Bose-Einstein condensates: