“…18 articles introduce or extend a mapping language for transforming heterogeneous (semi-)structured data into a knowledge graph [98,86,36,30,132,87,83,81,128,15,46,90,41,51,135,104,19]. 16 articles introduce data transformations or align them with a mapping language for heterogeneous (semi-)structured data [99,86,38,132,87,107,70,73,32,15,90,41,40,95,39,7]. 21 articles describe a materialization system [85,86,30,132,107,122,87,83,81,115,45,72,54,46,114,120,64,…”