which scientist is known for the routing in the pstn and the routing in the pstn ?
select distinct var_uri where brack_open var_uri dbo_knownFor dbr_Routing_in_the_PSTN sep_dot var_uri rdf_type dbo_Scientist sep_dot var_uri dbo_knownFor dbr_Routing_in_the_PSTN sep_dot brack_close