Data base infological design in practice
Laast-Laas, Jüri
Data processing, compiler writing, programming
1986
/
p. 107-112
https://www.ester.ee/record=b1275336*est
https://digikogu.taltech.ee/et/Item/2f07e0bc-df93-4429-80b8-c48c8a98986b