[1] Z. HEDRLÍN A. PULTR: On full embeddings of categories of algebras. Illinois J. of Math. 10, 3 (1966), 392-406. MR 0191858

[2] Z. HEDRLÍN A. PULTR: Symmetric Relations (Undirected Graphs) with Given Semigroups. Monatshefte f. Math. 69, 4 (1965), 318-322. MR 0188082

[3] Z. HEDRLÍN A. PULTR: On categorial embeddings of topological structures into algebraic. Comment. Math. Univ. Carolinae 7, 3 (1966), 377-400. MR 0202797

[4] J. R. ISBELL: Adequate subcategories. Illinois J. of Math. 4 (1960), 541-552. MR 0175954 | Zbl 0104.01704

[5] J. R. ISBELL: Subobjects, adequacy, completeness and categories of algebras. Rozprawy matematyczne XXXVI, Warszawa 1964. Zbl 0133.26703

[6] A. PULTR: On selecting of morphisms among all mappings between underlying sets of objects in concrete categories and realisations of these. Comment. Math. Univ. Carolinae 8, 1 (1967), 53-83. MR 0210764

[7] A. PULTR: Limits of functors and realisations of categories. Comment. Math. Univ. Carolinae 8, 4 (1967), 663-682. MR 0229689 | Zbl 0189.01801

[8] A. PULTR: Eine Bemerkung über volle Einbettungen von Kategorien von Algebren. submitted to Math. Annalen. Zbl 0174.30002

[9] P. VOPĚNKA A. PULTR Z. HEDRLÍN: A rigid relation exists on any set. Comment. Math. Univ. Carolinae 6 (1965), 149-155. MR 0183647