edited by Bryce S. Dewitt, Raymond Stora
North-Holland Amsterdam, 1984
Buku Teks
Penrose, Roger, author
Society for Industrial and Applied Mathematics, 1987
eBooks
Cambridge University Press, 2005
Buku Referensi
edited by Jean-Marie Henckaerts and Louise Doswald-Beck
Cambridge University Press, 2005
Buku Teks
edited by Michael J. Collins
Academic Press, 1980
Buku Teks