00447naa#a2200157#i#450# EN\\bibl\17440 20240911135206.3 1609-3178 20170712b2017####ek#y0engy0150####ca RU NDT Natural Oscillation Technique for Wooden Pole Strength Journal article Saint-Petersburg LLC SVEN 2017 3 с. Journal article local Kugushev Vladimir I. naukaru.ru