Dr. Monk's DIY Electronics Blog: TI Programmable 57 Calculator Battery Conversion
MyCalcDB : Calculator Texas Instruments TI-57 II version 3
Texas Instruments TI Programmable 57 Calculator W/ Case Instructions | eBay
Virtual Museum of Calculators
ET-57
Introduction to programming, TI Programmable 57 by Texas Instruments [1977] {510.28542--oclc} : Texas Instruments : Free Download, Borrow, and Streaming : Internet Archive