What is the test for the admissibility of constitutional reference materials in the context of constitutional references?

In justifying the admissibility of such materials, Dickson J. made reference to the “living tree” doctrine of progressive constitutional interpretation (at 723): A constitutional reference is not a barren exercise in statutory interpretation. What is involved is an attempt to determine and give effect to the broad objectives and purpose of the Constitution, viewed as a “living tree”, in the expressive words of Lord Sankey in Edwards and Others v. Attorney-General for Canada and Others. Material relevant to the issues before the court, and not inherently unreliable or offending against public policy should be admissible …