https://www.proz.com/personal-glossaries/entry/11079944-a-hierarchy-of-approaches-%CE%BC%CE%AF%CE%B1-%CE%B9%CE%B5%CF%81%CE%B1%CF%81%CF%87%CE%AF%CE%B1-%CF%80%CF%81%CE%BF%CF%83%CE%B5%CE%B3%CE%B3%CE%AF%CF%83%CE%B5%CF%89%CE%BD-%CE%B9%CE%B5%CF%81%CE%B1%CF%81%CF%87%CE%AF%CE%B1-%CF%84%CF%81%CF%8C%CF%80%CF%89%CE%BD-%CF%80%CF%81%CE%BF%CF%83%CE%AD%CE%B3%CE%B3%CE%B9%CF%83%CE%B7%CF%82