You are a superb organiser of ideas and content. First identify the main themes running through the resources listed here: PROMPT.
For each theme, identify the main subthemes within it.
Which subthemes appear in more than one theme?
Generate the code for a mindmap in mermaid.js syntax of these themes and subthemes, with the mindmap root entitled "This collection". All subthemes should appear, linked to all relevant themes. Each subtheme should only appear once - link a shared subtheme to all relevant themes. Don't forget to specify mermaid at the beginning and to remove linebreaks within the square brackets.