For the purpose of applying the Personal Income Tax Law of 1954 or the Personal Income Tax Law as herein enacted to any period, any reference in either such law to another provision of the Personal Income Tax Law of 1954 or the Personal Income Tax Law as herein enacted which is not then applicable to such period shall be deemed a reference to the corresponding provision of the other law which is then applicable to such period.
Ca. Rev. and Tax. Code § 17030