Classification Lenoch

"The system comprises forty-six main groups, which are represented by a two letter code. This code is based on the French version of the descriptors. Each main group can be divided into thirty-four subgroups which are represented both by the digits 1 to 9 and the letters A to Z (‘I’ was omitted in order to avoid confusion). The result is a three character code of high mnemonic value, especially since the third character is inheritable in meaning."