The thermal resistance between cables and a surrounding pipe or duct wall

[1]  Thermal Characteristics of a 120-Kv High-Pressure, Gas-Filled Cable Installation , 1948, Transactions of the American Institute of Electrical Engineers.

[2]  J. H. Neher.  The Temperature Rise of Cables in a Duct Bank , 1949, Transactions of the American Institute of Electrical Engineers.