-- [[https://commons.wikimedia.org/wiki/File:Technical_drawing_templates_(ISO_5457_1999_Sizes_A0-A4).pdf][BK-2020-04-PID-1]]: Chemical engineering symbols (ISO 10628-2:2012 Symbols)
-- [[https://commons.wikimedia.org/wiki/File:Technical_drawing_templates_(ISO_5457_1999_Sizes_A0-A4).pdf][BK-2020-04-TMP-1]]: Technical drawing templates (ISO 5457:1999 Sizes A0—A4)
-
-** Directories
-
-*** [[File:DEL][~DEL~]] : Deliverables
-May include drawings exported into PDF format.
-*** [[File:DWG][~DWG~]] : Drawing source files
-May include Inkscape SVG files.
-*** [[File:IMG][~IMG~]] : Reference image files
-May include various image files used in creation of project source
-files.
-
+- [[https://commons.wikimedia.org/wiki/File:ISO_10628-2_2012_Symbols.pdf][~BK-2020-04-PID-1~]]: Chemical engineering symbols ([[https://en.wikipedia.org/wiki/ISO_10628][ISO 10628]]-2:2012 Symbols)
+- [[https://commons.wikimedia.org/wiki/File:Technical_drawing_templates_(ISO_5457_1999_Sizes_A0-A4).pdf][~BK-2020-04-TMP-1~]]: Technical drawing templates (ISO 5457:1999 Sizes A0—A4)
+
+** Contents
+*** Directories
+- ~DEL~: Deliverables. A directory that may include plain SVG files
+ and exported PDF files. This is probably what you want.
+- ~DWG~: Drawing source files. A directory that may include [[https://inkscape.org/][Inkscape]]
+ SVG files.
+- ~EXEC~: Executable files. A directory that may include scripts
+ useful for manipulating files.
+- ~IMG~: Reference image files. A directory that may include various
+ image files used in creation of project source files.
+*** Files
+- ~README.org~: This file.
+- ~REVISIONS.org~: A file containing a detailed version history of
+ each drawing.
+- ~TODO.org~: A file containing a list of pending tasks for the
+ project.
+
+** Usage
+*** Generate a combined PDF
+A script is available at ~./EXEC/combine_pdfs.sh~ to merge multiple
+single-page PDFs into a single PDF file; the script uses the [[https://www.pdflabs.com/tools/pdftk-the-pdf-toolkit/][~pdftk~
+utility]] available on typical [[https://www.debian.org/][Debian]]-based [[https://en.wikipedia.org/wiki/Gnu-Linux][GNU/Linux]] machines
+of 2023. On a typical Debian 12 system, the following command may be
+used to merge ~input1.pdf~ and ~input2.pdf~ files into ~output.pdf~.
+
+: $ /bin/bash combine_pdfs.sh output.pdf input1.pdf input2.pdf