slightly more standard data merge: Symtax.merge (K true) avoids equality on abstract type Pretty.T and gracefully accepts overriding, Symtab.join prefers first entry as usual;
By chapter:
chapters 1 and 2, maybe 3: Peter White
chapters 6, 7 and 8: David von Oheim
chapter 6, maybe 8: Gerwin Klein
chapters 3, maybe 4: Tanja Vos
chapters 1-3 at least: Stefano Bistarelli