hirschIndex(Array of int citations)
    k = 0
    counter = 0
    //array including all quoted publications
    int a[citations.length]
    MergeSort(citations, 1, citations.length)
    for i = 1 to i = citations.length do
        //if publication is different than the previous one, increase counter
        if i - 1 > 1 AND citations[i] IS NOT citations[i-1] then
            counter = counter + 1
        end if
        //increase the number of citations of the current publication
        a[counter] = a[counter] +1
    end for
    MergeSort(a, 1, a.length)
    //find out hirschIndex
    for i = a.length down to 1 do
        //if the current publication is quoted more than k times, increase k
        if a[i] > k then
            k = k + 1
        end if
        //if k is now greater than a[i] return k, no following publication is quoted more often than a[i] (a was sorted before)
        if k >= a[i] then
            return k
        end if
    end for

    return 0