@inbook{
    ukkonen09edbs,
    author = "Ukkonen, Antti",
    chapter = "Frequent Partial Orders",
    publisher = "Springer",
    optmonth = "",
    optnumber = "",
    title = "Encyclopedia of Database Systems",
    optnote = "",
    optaddress = "",
    opttype = "",
    optedition = "",
    optpages = "",
    alteditor = "",
    flags = "ALGODAN HIIT",
    optkey = "",
    year = "2009",
    optvolume = "",
    impactfactor = "C",
    corerank = "NA",
    optannote = "",
    optseries = ""
}