Leibniz, G.W. von..
Discource on Metaphysics Correspondence with Arnauld and Monadology /
with an Intr. by P.Janet. Transl. by Dr. G.R.Montgomery 
. - Le Salle; Illinois : The Open Court Publishing Company,  1968 
. - XXIII, 272 p.  20 cm. 
 - ((The Open Court Library of Philosophy). )