Choy, C. L., & Yovanovich, M. . (1989). Microcomputer Computation of Natural Convection Heat Transfer from Isothermal Spheres into Air for Rayleigh Numbers from 1.5 to 10^7. In Numerical Heat Transfer with Personal Computers and Supercomputing: Vol. 110 (Vol. 110, pp. 87-93). Philadelphia, PA: ASME National Heat Transfer Conference.