Below is an explanation of a "deferred tax asset" (b) and a "deferred tax liability", taken from a brief summary of FASB-96 available on the Rutgers University Website (RAW).

The tax benefit of temporary differences that will result in deductible amounts in future years is recognized in the following circumstances:
a. A deferred tax liability is reduced to the extent that those deductible amounts offset taxable amounts from other temporary differences in future years.
b. A deferred tax asset is recognized to the extent that net deductible amounts in future years would be recoverable by a carryback refund of taxes paid in the current or prior years.
A deferred tax asset is not recognized for any additional amount of temporary differences that will result in net deductible amounts in future years. That additional amount is, in substance, the same as a tax loss carryforward.
The results of applying the requirements of this Statement are sometimes described as asymmetrical because a deferred tax liability is always recognized for temporary differences that will result in net taxable amounts and a tax benefit is only recognized for temporary differences that will result in deductible amounts that reduce taxes otherwise paid or payable.

Other reference: Accounting Trends & Techniques published annually by the AICPA
Hope this helps.