@article{TMF_1997_113_2_a1,
     author = {P. Winternitz and A. Yu. Orlov},
     title = {$P_\infty$ algebra of {KP,} free fermions and 2-cocycle in the {Lie} algebra of pseudodifferential operators},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {231--260},
     publisher = {mathdoc},
     volume = {113},
     number = {2},
     year = {1997},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1997_113_2_a1/}
}