Hodge, P.J. & Jones, R.A., 1995
New British Beetles: species not in Joy’s practical handbook
Essential guide for the Coleopterist, giving corrections to the keys in Joy's Practical Handbook and references to more recent identification works and to descriptions of species omitted by Joy as being unknown, too rare, not British etc.
Every identification made using Joy's Handbook should be checked against this work and it is the first place to check when a beetle won't key out. It is equally applicable to old Royal Ent Soc handbooks.