@misc{mechanism+of+behaviour+of+biological+sludge+in+an+ultrasonic+field,
    author = {Fryźlewicz-Kozak, Beata i Tal-Figiel, Barbara},
    title = {Mechanism of behaviour of biological sludge in an ultrasonic field},
    journal = {Czasopismo Techniczne. Mechanika},
    address = {Kraków},
    publisher = {<a href=\"http://www.wydawnictwo.pk.edu.pl/\" target=\"_blank\">Wydawnictwo PK</a>},
    date = {2008},
    number = {R. 105, Z. 6, 5-M}
}