1
Cyhoeddwyd: 1988.
Links: Cael y testun llawn
2
Cyhoeddwyd: [2019]
Superior document: Title is part of eBook package: De Gruyter University of Toronto Press eBook-Package Archive 1933-1999
Links: Cael y testun llawn; Cael y testun llawn; Cover
3
Cyhoeddwyd: [1930]
Superior document: Title is part of eBook package: De Gruyter CUP eBook Package Archive 1898-1999 (pre Pub)
Links: Cael y testun llawn; Cover
4
Cyhoeddwyd: [2016]
Superior document: Title is part of eBook package: De Gruyter Columbia University Press Complete eBook-Package 2016
Links: Cael y testun llawn; Cael y testun llawn; Cover