by Petkov, Ts.I, Bukrzev, K.N
Published in Nauchni trudove - Vissh institut po mashinostroene, mekhanizatsiia i elektrifikatsiia na selskoto stopanstvo (1981)

by Petkov, Ts.I, Ivanov, Ts.I, Tsankov, Ts.P
Published in Nauchni trudove - Vissh institut po mashinostroene, mekhanizatsiia i elektrifikatsiia na selskoto stopanstvo (1981)

by Lilov, Ts.S, Petkov, Ts.I, Bursev, K.N
Published in Nauchni trudove - Vissh institut po mashinostroene, mekhanizatsiia i elektrifikatsiia na selskoto stopanstvo (1981)

by Trifonov, T.A, Petkov, Ts.I, Dimitrov, A.I, Zlatev, Z. Kh
Published in Nauchni trudove - Vissh institut po mashinostroene, mekhanizatsiia i elektrifikatsiia na selskoto stopanstvo (1981)

by Dimitrov, S.D, Petkov, Ts.I, Stankov, E.P, Petrov, V
Published in Nauchni trudove - Vissh institut po mashinostroene, mekhanizatsiia i elektrifikatsiia na selskoto stopanstvo (1981)