Andreas Rozek
[ Imprint ]   [ Data Privacy Statement ]   [ Contact ]       [ deutsche Fassung ]   english version


The pages of this website have a number of (hopefully) useful functions. The following sections explain how to use them.


In the header and footer of each web page you will find links that provide helpful information or help you navigate to important other pages.

Fig. 1: Header of a Web Page
Fig. 1: Header of a Web Page
1tapping on the author's name will take you back to the home page
2a click on "Imprint" leads you to the imprint of this website
3click here to read the data privacy statement for this website.
4by tapping on "Contact" you will be taken to a form which you can use to contact the author
5a clearly visible, framed flag indicates that a translation is available for this page - tap on it to go to this translation. If, on the other hand, the flag is only dimly visible (and not framed), the page has not yet been translated.
6the clearly visible, unframed flag indicates the language of the present web page (either German or English)
Fig. 2: Footer of a Web Page
Fig. 2: Footer of a Web Page
7at the bottom left of a page you will find the corresponding URL
8the date at the bottom right of a page shows the time of the last update

Links to external Pages

Links to external pages are usually preceded by a - with the exception of links to articles in Wikipedia, which are preceded by a .


Apart from (JavaScript) applets, which are located on individual web pages and whose operation is explained on the spot, all pages of this website offer the following functions:

  • the folding in and out of chapters,
  • the showing and hiding of annotations as well as
  • the creation of personal notes by the visitor.

JavaScript is not required to show and hide chapters and notes, but it is required to create notes.

Folding in and out of Chapters

Some chapters on the author's web pages can be "collapsed". This means that only a short section of the respective chapter is displayed, while the rest is hidden.

You can recognize such chapters by the symbols or in the upper right corner of the respective chapter.

 indicates a collapsed chapter - tap the icon to make the related chapter fully visible again
 indicates a collapsed chapter - tap the icon to reduce the associated chapter to the introductory text

Show and hide Annotations

Many texts contain passages that provide further information or technical details and are not of permanent interest to everyone. In order not to overload the running text with ballast, these passages are often hidden in "annotations" which can be shown or hidden as required.

You can recognize such places by a "marker" in the form annotation below a text section. When this marker is clicked for the first time, the actual content of the annotation is shown, when it is clicked again, it is hidden.

This is a visible annotation. Tap the associated (now highlighted) marker to hide the annotation again.

Personal Notes

Provided JavaScript is enabled and local data storage has been permitted in the browser (see below), you can add personal comments and notes to individual sections of text.

You can recognize the availability of this function by the symbols or in the upper right corner of the section. If these symbols are missing, either JavaScript is switched off or the consent for local data storage in the browser is missing.

The first time such a symbol is clicked, a (possibly empty) note is displayed, it is hidden when the symbol is clicked again.

The symbol indicates that a (non-empty) note is available for the section in question, while the symbol indicates the absence of a note.

Entering a Note

If you want to create a new note or modify an existing note, first tap on the note icon assigned to the desired section (to open the note), and then tap in the text area of the note itself (to activate the editor).

Your entries are saved immediately, it is not necessary to explicitly save the note(s).

If you want to remove a single note, simply delete all text from that note.

The note is closed either by clicking on the symbol or by clicking again on or .

Local Data Storage in the Browser

This website does not use any cookies - no data is sent back to the delivering server.

If an applet nevertheless requests data from the Internet or sends it there, you will be explicitly informed of this beforehand.

However, personal data can be stored on the local computer at your express request ("opt-in").

Stored Data

Stored data includes:

  • the visibility of collapsible and expandable paragraphs
  • the visibility of foldable annotations
  • the content and visibility of personal notes, and
  • any data stored by applets.

Data Privacy

The stored data is linked to your user account and the browser you are using. Provided no other user can access your account and browser, this data is private - as private as the operating system used allows.

Usually, there are only a few reasons against storing data in the browser. Such reasons can be:

  • the use of a general user account on a computer accessible to the public (e.g. in a library or a hotel),
  • the use of a general user account on a computer used by several persons (e.g. family members) or
  • the use of a tablet used by several persons without user administration.

You may manage the stored data either in the Settings for this website or further down on this page.

Consent to (or Refusal of) Data Storage

Consent to data storage in the browser (or its revocation) can be given from (almost) every page of this website.

If a previously given consent to data storage is revoked, all stored data will be deleted immediately and irretrievably - a prior security query is intended to prevent accidental data loss.

Consent to Data Storage

By placing a cross in the box below, you agree to data storage in the browser for all pages of this website. By deleting the cross you revoke this consent.

Save Data of all Pages of this Website in the Browser.

Data Backup

Since the stored data is linked to the browser used, it may also be deleted accidentally (e.g. together with cookies).

For this reason, it is possible to write the data stored for all pages of this website to a file and to read it again from there later.

Backing up saved Data

By clicking the following button, you write the data saved for all pages of this website to a file in the download area of your browser.

Restoring saved Data

After clicking the button shown, you can select a file and restore the saved data from it for all pages of this website.

Previously saved data is overwritten - a prior confirmation request is intended to prevent accidental data loss.

Back up often!

Since the disappearance of data stored in the browser cannot be controlled (and especially prevented) by the author, it is advisable to make regular backups - especially of the notes entered.