By Ribes Tovar, Federico.
New York : Plus Ultra Educational Publishers , 1974 .
288 p., [16] leaves of plates , Includes index.

By Cupit, Aarón..
[Buenos Aires] Editorial Plus Ultra 1979 .
124 p. 24 cm..

New York, N.Y. Plus Ultra Educational Publishers 1970 .
157 p. , Place of publication from label on verso of t.p. 22 cm..
0915534258 (pbk.)

By Ribes Tovar, Federico.
New York : Plus Ultra Educational Publishers, 1973 .
606 pages : 18 cm..

By Alvarez González, Francisco.
San José Universidad Autónoma de Centro América 1992 .
798 p. , Ediciones del Quigentésimo Americano. 9977630615

By Nervi, Juan Ricardo..
Buenos Aires Editorial Plus Ultra 1981 .
172 p.

By Ribes Tovar, Federico.
New York, N.Y. Plus Ultra Educational Publishers 1972 .
251 p.

By Bloch, Peter..
New York Plus Ultra Educational Publishers 1973 .
197 p. 18 cm..

By Moretti, Darcia..
[New York] Plus Ultra Education 1973 .
220 p.

By Ribes Tovar, Federico.
[New York] Plus Ultra Educational Publishers 1973 .
304 p.

By Bloch, Peter..
New York Plus Ultra Educational Publishers 1973 .
197 p. 18 cm..

By Bloch, Peter..
New York : Plus Ultra Educational Publishers , 1973 .
197 p. 18 cm..