Extreme vortex pinning in the non-centrosymmetric superconductor CePt$_{3}$Si
Extremely high sensitivity to uniaxial stress in pressure induced superconductivity of BaFe2As2
Extremely strong coupling superconductivity in artificial two-dimensional Kondo lattices
Extremely strong-coupling superconductivity and anomalous lattice properties in the beta-pyrochlore oxide KOs2O6