english: The answer to the question put to me by L.V. Ovsyannikov 33 years ago2007Conference paper (Refereed)
non_english: ➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡SOI CẦU ➡ RONGBACHKIM.ASIA ➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡➡