70 Pa. Code § 23.107
Wood used for fuel shall be sold by the cord of 128 cubic feet, or fraction thereof, and shall be accompanied by a statement or invoice certifying the amount sold and presented to the buyer or his designee at the time of delivery or billing.
The provisions of this § 23.107 adopted October 21, 1970, effective October 22, 1970, 1 Pa.B. 44.