Your best bet would be to try an out of print book search, or purchase a photocopy from Spring. I know that Daimon Verlag, our European distributor has a few copies of Spring from the 70s. Please contact Eliane at for further details and purchasing information. I know it's not much, but I hope my response was somewhat helpful. Please contact me with further questions if you should have any.
Most older issues are out of print and sold out.
Your best bet would be to try an out of print book search, or purchase a photocopy from Spring. Please contact me with further questions if you should have any.