There is one main library that is required for all amCharts operations - amcharts.js. It needs to be included first and is mandatory.
Each chart type requires chart-type specific include. For example Serial chart, will also require serial.js, a Pie chart will need pie.js, etc.
If on the same web page you will be displaying several different chart types, you will need to include all chart-type-specific includes that are being displayed on that page.