An html version of Valladao.cql; Created by Gady Costeff and Lewis Stiller.

CQL 5.1
; castling, enpassant and underpromotion occur in the main line cql(input heijden.pgn) initial flipcolor next* {move from Ke1 to g1 or c1 comment "CASTLE"} next* {move enpassant comment "ENPASSANT"} next* {move promote [RBNrbn] comment "UNDERPROMOTION"}

CQL 3.2
; The Valladao task: find studies in which en-passant, underpromotion, and castling all occur in the main line. (match :pgn heijden.pgn :output valladao.pgn (position :enpassant) (position :movefrom [Kk]e? :moveto .[c?,g?] ) (position :promote [NnBbRr]) )

After executing this with "> cql Valladao.cql" there are 22 studies found in the Harold van der Heijden Database 2015.
NB. When you see {MATCH} in the text, it means that cql has found the position asked for.

Below only 5 studies are presented: