Structural changes in the solar corona during the july 1991 eclipse - Zirker, J B; Koutchmy, S; Nitschelm, C; Stellmacher, G; Zimmermann, J P; Martinez, P; Kim, I S; Dzubenko, N I; Kurochka, L; Mararov, V; Fatianov, M (Astronomy and Astrophysis, 1992)