Geymonat, Giuseppe; Grubb, Gerd Spectral theory for boundary value problems for elliptic systems of mixed order. (English) Zbl 0301.35071 Bull. Am. Math. Soc. 80, 1255-1259 (1974). MSC: 35P20 58J10 35J55 × Cite Format Result Cite Review PDF Full Text: DOI
Grubb, G. Coerciveness of the normal boundary problems for an elliptic operator. (English) Zbl 0188.16902 Bull. Am. Math. Soc. 76, 64-69 (1970). × Cite Format Result Cite Review PDF Full Text: DOI