Critical points of the elements (data page)

CRC.a-d
David R. Lide (ed), CRC Handbook of Chemistry and Physics, 85th Edition, online version. CRC Press. Boca Raton, Florida, 2003; Section 6, Fluid Properties; Critical Constants. Also agrees with Celsius values from Section 4: Properties of the Elements and Inorganic Compounds, Melting, Boiling, Triple, and Critical Point Temperatures of the Elements
 * Estimated accuracy for Tc and Pc is indicated by the number of digits. Above 750 K Tc values may be in error by 10 K or more. Vc values are not assumed accurate more than to a few percent. Parentheses indicate extrapolated values. From these sources:
 * (a) D. Ambrose, Vapor-Liquid Constants of Fluids, in R.M. Stevenson, S. Malanowski, Handbook of the Thermodynamics of Organic Compounds, Elsevier, New York, (1987).
 * (b) I.G. Dillon, P.A. Nelson, B.S. Swanson, J. Chem. Phys. 44, 4229, (1966).
 * (c) O. Sifner, J. Klomfar, J. Phys. Chem. Ref. Data 23, 63, (1994).
 * (d) N.B. Vargaftik, Int. J. Thermophys. 11, 467, (1990).

LNG
J.A. Dean (ed), Lange's Handbook of Chemistry (15th Edition), McGraw-Hill, 1999; Section 6; Table 6.5 Critical Properties

KAL
National Physical Laboratory, Kaye and Laby Tables of Physical and Chemical Constants; D. Ambrose, M.B. Ewing, M.L. McGlashan, Critical constants and second virial coefficients of gases (retrieved Dec 2005)

SMI
W.E. Forsythe (ed.), Smithsonian Physical Tables 9th ed., online version (1954; Knovel 2003). Table 259, Critical Temperatures, Pressures, and Densities of Gases