@article{Jankiewicz:2009,
author
=
"J.Jankiewicz and K.Urbanowski",
title
=
"On Khalfin's improvement of the LOY effective Hamiltonian for neutral meson complex",
journal
=
"European Physical Journal C",
volume
=
"Vol. 49",
pages
=
"721--730",
year
=
"2007",
}