TY  - DATA
AU  - Freese, Ralph S.
TI  - The structure of modular lattices of width four with applications to varieties of lattices 
T2  - Memoirs of the American Mathematical Society, 
SN  - 9781470408640 (online)
PY  - 1977///
CY  - Providence, R.I.
PB  - American Mathematical Society
UR  - http://www.ams.org/memo/0181
ER  -