1. Gravity measurements in North America with the Cambridge pendulum apparatus I;Garland;Proc. R. Soc., A.,1953
2. Gravity measurements in North America with the Cambridge pendulum apparatus, II;Garland;Proc. R. Soc, A,1955
3. Hales, A. L., , D. L., Gough, , Measurements of gravity in South Africa, Govt Printer, Pretoria, 1950,
4. Gravity values obtained with the Gulf quartz pendulums over the North American gravity range;Rose,1955