The utility suite collects several basic programs into one file, which were sourced from various places:
*The Z80 disassembler is code from R.A Waddilove which was first included in "Computing with the Amstrad", November 1985. ([https://acpc.me/ACME/LITTERATURE_REVUES/[ENG]ENGLISH_UK%5BENG%5DENGLISH_UK/[ENG][AMSTRAD]COMPUTING_WITH_THE_AMSTRAD%5BENG%5D%5BAMSTRAD%5DCOMPUTING_WITH_THE_AMSTRAD/COMPUTING_WITH_THE_AMSTRAD(UK_Version)_1985-11[OCR]%5BOCR%5D.pdf|Read on ACME.ME])
*The Print Catalog code is from John Campbell, published in "Amstrad Computer User", October 1985 ([https://archive.org/details/AmstradComputerUser11-1085/page/n3/mode/2up Read on Archive.org ])