四分律行事鈔資持記 2.312

2.312

四中。盜寫祕方，此非經教，與法類故；須約前人悋護，計直定犯。

In the fourth: secretly copying secret recipes—these are not scriptural teachings, but are of the same class as texts; one must evaluate the other person's miserly guarding, estimate the value, and determine the offense.