Lamp substitution guide.
Contributors: Ontario Hydro.
Edition: 2nd ed.
Series: In-house energy efficiency
Publisher: Ontario Hydro
Place of publication: [Toronto
Language: eng
Subjects: Lighting -- Energy conservation.; Lighting -- Equipment and supplies.; Electric power -- Conservation.; Electric lighting -- Energy conservation.
Notes: Cover title.

"Save money by saving energy, calculate your savings."

Each double leaf contains a double faced slide rule card.