@article{1093891199,
author = {Sobel, Jordan Howard},
title = {Principia Mathematica description theory: the classical and an alternative notation.},
journal = {Notre Dame J. Formal Logic},
volume = {15},
number = {1},
year = {1974},
pages = { 63-72},
language = {en},
url = {http://dml.mathdoc.fr/item/1093891199}
}
Sobel, Jordan Howard. Principia Mathematica description theory: the classical and an alternative notation.. Notre Dame J. Formal Logic, Tome 15 (1974) no. 1, pp. 63-72. http://gdmltest.u-ga.fr/item/1093891199/