ON INSTANTANEOUS CODES, Stephan Foldes and Navin M. Singhi

Maximal instantaneous codes are characterized by the property that they allow unique parsing of every infinite string. The sequence of codeword lengths of a maximal instantaneous code, sequenced in lexicographic order of the codewords, completely determines the code itself. Any increasing, decreasing or unimodal reordering of such a sequence again corresponds to a maximal instantaneous code. Lexicographic length sequences are characterized by a family of  Kraft-type equalities.