How to merge lecture notes from the web into a single PDF file

I didn't really test this, but you could use a shell script instead.

#!/bin/bash

join="/System/Library/Automator/Combine PDF Pages.action/Contents/Resources/join.py"
date=$(date '+%Y-%m-%d')
last=$(ls ~/Desktop/$date*.pdf 2> /dev/null | tail -n1 | sed -E 's/.* 0*(.*)\.pdf$/\1/g' || 0)

cd ~/Documents/Scanned/
for f in scanf*.pdf; do
    ((last++))
    output="$HOME/Desktop/$date $(printf %03d $last).pdf"
    python "$join" -o "$output" "$f" "${f/scanf/scanb}"
    osascript -e 'on run {f}
tell app "Finder" to set label index of (posix file f as alias) to 2
end' "$output"
done

on run
    set cat to value of variable "cat" of front workflow (*I have already defined the variable elsewhere in the workflow*)
    set num to {}
    set myString to ""
    tell application "Contacts"
        repeat with i in cat
            set inGroup to group i
            set phoneProps to value of phones of inGroup's people
            repeat with i in phoneProps
                try
                    set myString to myString & "\n" & first item of i (*gets first number only*)
                on error
                    set myString to myString & "\n" & "blank field" (*covers for empty phone number, otherwise would halt on error*)
                end try
            end repeat
        end repeat
        return myString
    end tell  
end run