Which suggests that perhaps there were other, non-cryptographic reasons why the Army continued to use chart and book based systems.

The point appears to be first named on a chart based upon DI surveys undertaken in the period 1926-30.

The name appears on a chart based upon a survey by DI personnel in 1930.

The name is first used on a chart based upon survey work by DI personnel in 1926-30.

This chart, based on Transparency International figures, is helpful.

The name appears on a 1829 chart based upon survey work by the British expedition under Foster, 1828-31.

The name appears on a chart based upon surveys by DI personnel in the period 1926-30.

The name appears on a chart based upon 1929-30 surveys by DI personnel, but may reflect an earlier naming.

A large number of the countdowns are Top 22 charts based on ratings from country to country.

The name appears on a chart based upon surveys of this area in 1930 by DI personnel, but may reflect an earlier naming.