|Cosmology Applet - Related Links|
A good review of the cosmological constant can be found in "The Cosmological Constant" by Carroll, Press, and Turner, Annual Reviews of Astronomy and Astrophysics, 30, 499 (1992)
The observational projects which have indicated that there may be a non-zero cosmological constant include the Supernova Cosmology Project and the High Redshift Supernova Search The algorithms for calculating ages and lookback times for universes with arbitrary values of the cosmological parameters can be found in "The Age-Redshift Relation for Standard Cosmology" by Thomas and Kantowski. They also have Fortran 90 algorithms to calculate things.
Note that for universes with OmegaL=0, the calculations are much simpler; algorithms can be found, for instance, in "An Introduction to Modern Astrophysics" by Carroll and Ostlie.
Age estimates for LBDS 53W091 can be found in LBDS 53W091: an Old, Red Galaxy at z=1.552by Spinrad etal 1997 (ApJ, 484, 581). These estimates have been updated in On the Age Estimation of LBDS 53W091 by Yi etal 2000 (ApJ, 533, 670).