(a) Subject to the following conditions, nonresidents shall be allowed a credit against the “net tax” (as defined by Section 17039) for net income taxes imposed by and paid to the state of residence (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 if the state of residence either does not tax income of residents of this state derived from sources within that state or allows residents of this state a credit against the taxes imposed by that state on such income for “net tax” (as defined by Section 17039) paid or payable thereon under this part.
2. (2) The credit shall not be allowed for taxes paid to a state which allows its residents a credit against the taxes imposed by that state for “net tax” (as defined by Section 17039) paid or payable under this part irrespective of whether its residents are allowed a credit against the taxes imposed by this part for income taxes paid to that state.
3. (3) Credit shall be allowed only for such proportion of the taxes paid to the state of residence (not including any preference, alternative, or minimum tax comparable to the tax imposed by Section 17062) as the income taxable under this part and also subject to tax in the state of residence bears to the entire income upon which the taxes paid to the state of residence are imposed.
4. (4) The credit shall not exceed such proportion of the “net tax” (as defined by Section 17039) payable under this part as the income subject to tax in the state of residence and also taxable under this part bears to the entire income taxable under this part.
5. (5) No credit shall be allowed under this section for any tax imposed by Section 17062.