Complex sentence: The excavation was performed by G. Rosenberg, conservator, and P. Helweg Mikkelsen, pharmacist, between 1934 and 1937 and their original drawings constitute the primary source-material for information on the find.
Split into simpler sentences: The excavation was performed by G. Rosenberg, conservator, and P. Helweg Mikkelsen, pharmacist, between 1934 and 1937. Their original drawings constitute the primary source-material for information on the find.