1871/1970, a decent mainly mint collection in an Yvert album, well collected throughout from early issues and more or less complete, several varieties noted (e.g. nice study of 1881 5c. on ½c. green), also a good section Back of Book. (Image)

1871/1990 (ca.), used and mint collection/accumulation on leaves/in stockbook, main value in pre-1950 issues with plenty of interesting material from early issues, overprints, airmails, commemoratives etc. (Image)

1879/1881, QUETZAL ISSUES, used and mint collection/assortment of apprx. 1.270 stamps of all denominations, showing a great range of postmarks (incl. forged), flaws, multiples, imprint blocks etc. (Image)