See on the french ukulele forum this method from 1919 by Henry A. Bishaw, here is a nice waltz from it.
link to the "Albert Ukulele method" :
http://nla.gov.au/nla.mus-vn2867063
link to the "Albert Ukulele method" :
http://nla.gov.au/nla.mus-vn2867063