function drawChartTreatmentsPerSource() {
  var chartData = google.visualization.arrayToDataTable([
    ['Series', 'Number of Treatments'],
    ['Birkhaeuser Verlag', 3],
    ['Candollea', 3],
    ['Flora Helvetica', 3],
    ['Info Flora Schweiz', 4],
    ['Laurentius Salvius', 3],
    ['Order out of Chaos. Linnaean Plant Types and their Types', 2],
    ['Phytotaxa', 4],
    ['Taxon', 1]
  ]);
  var chartOptions = {
    pieHole: 0,
    title: 'Treatments per Journal (n=23)',
    fontSize: 'automatic',
    doWeHaveDanglingCommas: 'No ;-)'
  };
  if (window.customizeGoogleChartOptions)
    customizeGoogleChartOptions(chartOptions, 'TreatmentsPerSource', 'pie', 8, 0);
  var chart = new google.visualization.PieChart(document.getElementById('chartDivTreatmentsPerSource'));
  chart.draw(chartData, chartOptions);
}
google.load('visualization', '1', {'packages': ['corechart']});
google.setOnLoadCallback(drawChartTreatmentsPerSource);