(a) Subject to the following conditions, residents shall be allowed a credit against the “net tax” (as defined by Section 17039) for net income taxes imposed by and paid to another state (not including any preference, alternative, or minimum tax comparable to the tax imposed by Section 17062) on income taxable under this part:

1. (1) The credit shall be allowed only for taxes paid to the other state (not including any preference, alternative, or minimum tax comparable to the tax imposed by Section 17062) on income derived from sources within that state which is taxable under its laws irrespective of the residence or domicile of the recipient.

   This paragraph shall not apply to residents to whom subdivision (b) of Section 17014 applies.

2. (2) The credit shall not be allowed if the other state allows residents of this state a credit against the taxes imposed by that state (not including any preference, alternative, or minimum tax comparable to the tax imposed by Section 17062) for “net tax” (as defined by Section 17039) paid or payable under this part.
3. (3) The credit shall not exceed the proportion of the “net tax” (as defined by Section 17039) payable under this part as the income subject to tax in the other state (not including any preference, alternative, or minimum tax comparable to the tax imposed by Section 17062) and also taxable under this part bears to the taxpayer’s entire income upon which the “net tax” (as defined by Section 17039) is imposed by this part.
4. (4) No credit shall be allowed under this section for any tax imposed by Section 17062.