SP/k: A System for Teaching Computer Programming
SP/k is a compatible subset of the PL/I  language
that has been designed for teaching programming. 
The features of the SP/k language were chosen to encourage
structured problem solving by computers, to 
make the language easy to learn and use, to eliminate
confusing and redundant constructs, and to make 
the language easy to compile.  The resulting language
is suitable for in troducing programming concepts 
used in various applications, including business data
processing, scientific calculations and non-numeric 
computation.  SP/k is actually a sequence of language
subsets called SP/1, SP/2,...SP/8.  Each subset 
in troduces new programming language constructs while
retaining all the constructs of preceding subsets. 
Each subset is precisely defined and can be learned
or implemented without the following subsets.
CACM May, 1977
Holt, R. C.
Wortman, D. B.
Barnard, D. T.
Cordy, J. R.
