@book
{TN_libero_mab2,
author = {
Mallory, Virgil S.
},
title = {
The relative difficulty of certain topics in mathematics for slow-moving ninth grade pupils
},
publisher = {Bureau of Publications Teachers College, Columbia University},
keywords = {
Hochschulschrift
},
year = {1939},
booktitle = {Teachers College, Columbia University contributions to education ; 769},
address = {
New York
},
url = {
http://slubdd.de/katalog?TN_libero_mab2
}
}