*[A Practical Introduction to APL1 & APL2](http://robertson.uk.net) - Graeme Donald Robertson (PDF)
*[A Practical Introduction to APL1 & APL2](http://robertson.uk.net) - Graeme Donald Robertson (PDF)
*[A Practical Introduction to APL3 & APL4](http://robertson.uk.net) - Graeme Donald Robertson (PDF)
*[A Practical Introduction to APL3 & APL4](http://robertson.uk.net) - Graeme Donald Robertson (PDF)
*[Introduction to College Mathematics with A Programming Language (1978)](http://www.softwarepreservation.org/projects/apl/Books/CollegeMathematicswithAPL) - E. J. LeCuyer (PDF)