Piaget, Jean, author
Basic Books, 1970
Buku Teks
Köhler, Wolfgang, 1887-1967, author
Liveright, 1947
Buku Teks
Palmer, Donald D., author
Writers and Readers, 1997
Buku Teks
Routledge , 1990
Buku Teks
edited by Helen Castle
John Wiley & Sons, 2010
Buku Teks