00498naa#a2200169#i#450# EN\\bibl\14222 20240506112621.1 1999-8775 20150930b2015####ek#y0engy0150####ca RUS RU Periodic vibrations of nongomogeneous string with clamped and free ends. Journal article Bryansk Bryansk State Technical University 2015 9 с. Journal article local Rudakov Igor bstu.editorum.ru