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

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

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

By Ribes Tovar, Federico.
[s.l.] [s.n.] 1968 .
v. , English-Spanish.

By Ribes Tovar, Federico.
New York Arno Press 1980 .
496 p. 0405131674

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

By Ribes Tovar, Federico.
New York Plus Ultra Educational Publishers 1971 .
252 p.

By Ribes Tovar, Federico.
San Juan, P. R. Plus Ultra Educational 1970 .
3 v. , Spanish and English.

By Ribes Tovar, Federico.
New York Plus Ultra 1975 .
415 p.