Schwab, Glenn Orville, 1919-, author
John Wiley and Sons, 1996
Buku Teks
John Wiley and Sons, 1979
Buku Teks
Artikel Jurnal
Schwab, Glenn Orville, 1919-, author
New York: John Wiley & Sons, 1957
Buku Teks
Young, Anthony
Oxon CAB International, 1994
Buku Teks