Coulson, C.A.
Valence
Oxford University Press, 1972
 Buku Teks
Tanya Fitriyani
Tingkat kepadatan dalam Commuter Line serta hubungannya dengan fluktuasi valensi dan arousal penumpang = Level of density in Commuter Line and its relation with passengers valence and arousal fluctuations
2016
 UI - Skripsi (Membership)
Murrel, J.N.
Valence theory
John Wiley & Sons, 1965
 Buku Teks
Gordon, Robert Aaron
Business fluctuations
Harper & Brothers, 1952
 Buku Teks
Wilson, Ian
Engineering solids
McGraw-Hill, 1979
 Buku Teks