The Text

Every law which imposes, continues or revives a tax shall distinctly state the tax and the object to which it is to be applied, and it shall not be sufficient to refer to any other law to fix such tax or object.
Notwithstanding the foregoing or any other provision of this constitution, the legislature, in any law imposing a tax or taxes on, in respect to or measured by income, may define the income on, in respect to or by which such tax or taxes are imposed or measured, by reference to any provision of the laws of the United States as the same may be or become effective at any time or from time to time, and may prescribe exceptions or modifications to any such provision.