From the abstract — To develop a mathematical model for the determination of total areas under curves from various metabolic studies. Hint! If you replace phrases like "curves from metabolic studies" with just "curves", then you'll note that Dr. Tai rediscovered the rectangle method of approximating an integral. (Actually, Dr. Tai rediscovered the trapezoidal rule.). Apparently this is called "Tai's Model. This is also discussed here ."
Link to Original Source