Gerber RS-274X Format - Gerber data is a simple, generic means of transferring printed circuit board information to a wide variety of devices that convert electronics PCB data to atwork produced by photoplotter. Virtually every PCB CAD system generates Gerber data because all photoplotters read it. This book is in pdf format.
HART - process automation field communications protocol
Specification and Description Language (SDL) - an object-oriented, formal language defined by The International Telecommunications UnionTelecommunications Standardization Sector (ITU-T)