X = K under review

X, E, M, and P-Type Asteroid Spectral Observations

X- and gamma-ray emission from 3C 273

X-Exoplanets: An X-ray and EUV Database for Exoplanets

X-inner automorphisms of semi-commutative quantum algebras

X-method for klt surfaces in positive characteristic

X-ray absorption spectroscopy identifies calcium-uranyl-carbonate complexes at environmental concentrations

X-ray and optical properties of clusters of galaxies.

X-ray and radio structures in cooling flow clusters

X-ray and Radio Structures in Some Cooling Flow Clusters

X-ray and SZ Signatures of The Non-Equipartition Between Electrons and Ions in The Envelopes of Relaxed Galaxy Clusters

X-Ray and UV Orbital Phase Dependence in LMC X-3

X-ray astronomy and the AXAF space observatory

X-ray Astronomy and the IR Background

X-ray astronomy in the future

X-ray Binaries in Nearby Galaxies: Identifying Black Hole and Neutron Star Candidates

X-ray Binaries in the Central Region of M31

X-ray biosignature of bacteria in terrestrial and extra-terrestrial rocks

X-ray burst sources - A model for chaotic behaviour

X-Ray Bursts from Anomalous X-Ray Pulsars