[1] Z. HEDRLÍN A. PULTR V. TRNKOVÁ: 
Concerning a categorical approach to topological and algebraic theories. General Topology and its Relations to Modern Analysis and Algebra, II (Proc. Second Prague Topol. Symp., 1966), Academia, Prague, 1967, 176-181. 
MR 0230784[2] V. TRNKOVÁ J. REITERMAN: 
The categories of presheaves containing any category of algebras. to appear in Dissertationes Mathematicae. 
MR 0379622[3] Z. HEDRLÍN J. LAMBEK: 
How comprehensive is the category of semigroups. J. Alg. 11 (1969), 195-213. 
MR 0237611[4] A. PULTR J. SICHLER: 
Primitive classes of algebras with two unary idempotent operations, containing all algebraic categories as full subcategories. Comment. Math. Univ. Carolinae 10 (1969), 425-445. 
MR 0253969[5] J. SICHLER: Theses. Prague, 1968.
[7] P. VOPĚNKA A. PULTR Z. HEDRLÍN: 
A rigid relation exists on any set. Comment. Math. Univ. Carolinae 6 (1965), 149-155. 
MR 0183647[8] Z. HEDRLÍN A. PULTR: 
On full embeddings of categories of algebras. Illinois J. Math. 10 (1966), 312-406. 
MR 0191858