I know of two versions on the web:
http://www.retroarchive.org/cpm/lang/lang.htm has MBASREF.ZIP
http://apple2info.net/hardware/softcard/softcard.htm has
SC-MBAS_a2in.pdf
Scanned and available on the csa2 gmail account:
PSC2EBAS.PDF 5MB MBASIC manual for Premium Softcard IIe, 245 pages,
1983
SC-MBAS.PDF 4MB MS SoftCard BASIC Reference Manual
I have also scanned the Apple III CP/M manuals, but I do not remember
if I had the BASIC manual.
--
Paul R. Santa-Maria
Monroe, Michigan USA