@prefix skos:	<http://www.w3.org/2004/02/skos/core#> .
@prefix isac:	<http://webisa.webdatacommons.org/concept/> .
isac:huffman_code_	skos:broader	isac:variable-length_code_ .
isac:morse_code_	skos:broader	isac:variable-length_code_ .