function drawChartTreatmentsPerSource() {
  var chartData = google.visualization.arrayToDataTable([
    ['Series', 'Number of Treatments'],
    ['Christ. Gottl. Proft', 2],
    ['Eberhard Klett et Franck', 1],
    ['H. Steiner und Comp.', 1],
    ['Ioannis Thomae Trattner', 4],
    ['L. Salvius', 1],
    ['Laurentii Salvii', 5],
    ['Officina Libraria Kortii', 4],
    ['Proft et Storch', 5],
    ['Schneider', 1],
    ['Transactions of the Linnean Society of London', 2],
    ['Typis Hæredum Widmanstadii', 4],
    ['Weingand & Köpf', 1]
  ]);
  var chartOptions = {
    pieHole: 0,
    title: 'Treatments per Journal (n=31)',
    fontSize: 'automatic',
    doWeHaveDanglingCommas: 'No ;-)'
  };
  if (window.customizeGoogleChartOptions)
    customizeGoogleChartOptions(chartOptions, 'TreatmentsPerSource', 'pie', 12, 0);
  var chart = new google.visualization.PieChart(document.getElementById('chartDivTreatmentsPerSource'));
  chart.draw(chartData, chartOptions);
}
google.load('visualization', '1', {'packages': ['corechart']});
google.setOnLoadCallback(drawChartTreatmentsPerSource);