Westrup, J.A.
William Collins Sons, 1959
Buku Referensi
Wade-Matthews, Max
Southwater, 2013
Buku Teks SO
chapters by Edgar McInnis ... [et al.] ; edited by George W. Brown
University of California Press, 1953
Buku Teks SO
edited by George W. Brown
University of California Press, 1954
Buku Teks SO
Manzer, Ronald A.
McGraw-Hill Ryerson, 1974
Buku Teks