The document discusses keyword query routing for keyword search over multiple structured data sources. It proposes computing top-k routing plans based on their potential to contain results for a given keyword query. A keyword-element relationship summary compactly represents keyword and data element relationships. A multilevel scoring mechanism computes routing plan relevance based on scores at different levels, from keywords to subgraphs. Experiments on 150 public sources showed relevant plans can be computed in 1 second on average desktop computer. Routing helps improve keyword search performance without compromising result quality.