Brockhaus-1911: Neilgherry Hills · Ochill Hills · Pentland Hills · Lowther Hills · Black Hills · Cheviot Hills · Clee Hills
Eisler-1904: Two-aspects-theory
Meyers-1905: Mendip Hills · Moorfoot Hills · Lennox Hills · Louther Hills · Ochill Hills · Sidlaw Hills · Siwa lik Hills · Pentland Hills · Quantock Hills · Clee Hills · Clent Hills · Black Hills · Chiltern Hills · Cobequid Hills · Jaintia Hills · Lammermuir Hills · Cotswold Hills · Garo Hills
Pierer-1857: Two Groupps · Two-pence · Mendip-Hills · Lammermoor Hills · Moffat Hills · Quantocks-Hills · Pentland-Hills · Blue Hills · Black-Hills · Bardon Hills · Branden-Hills · Hills-River · Cossya-Hills · Chiltern-Hills