§ 22. 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.