Several editions in the Libray of Congress.
Search the catalogue for Lochamer and Locheimer.

From one of the best German music publishers:

Type of Material:         Printed Music
Brief Description:         Lochamer Liederbuch.
        Das Lochamer-Liederbuch / Einfuuehrung und Bearbeitung der Melodien von Walter Salmen ; Einleitung und Bearbeitung der Texte von Christoph Petzsch.
        Wiesbaden : Breitkopf & Haertel, 1972.
        lxxiv p., 133 p. of music ; 26 cm.
        
CALL NUMBER:         M2 .D413 Bd. 2
Copy 1
-- Request in:         Performing Arts Reading Room (Madison, LM113)
-- Status:         Not Charged

small edition:

LC Control Number:          75764816
Type of Material:         Book (Print, Microform, Electronic, etc.)
Brief Description:         Lochamer Liederbuch. [from old catalog]
        Das Lochamer-Liederbuch
        Kleine Ausg.
        Wiesbaden : Breitkopf & Haertel, 1973.
        xiv, 66 p. : fascim. ; 26 cm.
        
CALL NUMBER:         M1734.L78 L6
        Copy 1
-- Request in:         Performing Arts Reading Room (Madison, LM113)
-- Status:         Not Charged

from another trustworthy publisher:

LC Control Number:          75389611
Type of Material:         Book (Print, Microform, Electronic, etc.)
Brief Description:         Lochamer Liederbuch.
        Das Locheimer Liederbuch nebst der Ars Organisandi von Conrad Paumann,
        Wiesbaden, M. Saendig [1969]
        iv, 234 p. facsims., music. 22 cm.
        
CALL NUMBER:         M2 .L77
        Copy 1
-- Request in:         Performing Arts Reading Room (Madison, LM113)        
-- Status:         Not Charged


I've dissolved the umlauts.
For practising demisemiquavers you've got the wrong music; it is set for the organ, I presume, but not for folk music.