A few of the many Sutta references (hope the links are current):
Majjhima Nikaya 112 Chabbisodhana Sutta - The Six-Fold Examinationhttp://mail.saigon.com/~anson/ebud/majj ... hana-e.htm
Majjhima Nikaya 115 Bahudhatuka Sutta - The Many Kinds of Elementshttp://mail.saigon.com/~anson/ebud/majj ... tuka-e.htm
Majjhima Nikaya 140 Dhatu-vibhanga Sutta - The Exposition of the
Propertieshttp://mail.saigon.com/~anson/ebud/majj ... anga-e.htm
Majjhima Nikaya 148 Chachakka Sutta The Discourse of Six Sixeshttp://mail.saigon.com/~anson/ebud/majj ... akka-e.htm
Majjhima Nikaya 149 Mahaasa.laayatanika Sutta - The Longer Discourse
on the six sphereshttp://mail.saigon.com/~anson/ebud/majj ... nika-e.htm
Samyutta Nikaya XXII.56 Parivatta Sutta - The (Fourfold) Roundhttp://www.accesstoinsight.org/canon/sa ... 2-056.html
Samyutta Nikaya XXII.57 - Seven Baseshttp://www.accesstoinsight.org/canon/sa ... 2-057.html
Samyutta Nikaya 'The Connected Discourses of the Buddha'
beginning at page 627 Part III 14 Dhatu-samyutta (in The Book of
beginning at page 853 Part III 22 Khandha-vagga The Book of the
beginning at page 1133 Part IV 35 Salayatana-vagga The Book of the
Six Sense Bases
Some Visuddhimagga references:
P.547 of Visuddhimagga 'The Path of Purification' XVm, 1 'Description
of the Bases and Elements'
P.552 of Visuddhimagga 'The Path of Purification' XV,17
ff 'Description of the Bases and Elements'
P.649 of Visuddhimagga 'The Path of Purifiction' XVII, 203 [(v) The
Nyanatiloka in his Buddhist Dictionary defines dhatu, ayatana and
: 'elements', are the ultimate constituents of a whole. (I) The
4 physical elements (dhtu or mah-bhta), popularly called earth,
water, fire and wind, are to be understood as the primary qualities
of matter. <snip> (II) The 18 physical and mental elements that
constitute the conditions or foundations of the process of
: <snip>. The 12 'bases' or 'sources' on which depend the
mental processes, consist of five physical sense-organs and
consciousness, being the six personal (ajjhattika) bases; and the six
objects, the so-called external (bhira) baseskhandha
: the 5 'groups (of existence)' or 'groups of clinging'
(updnakkhandha); alternative renderings: aggregates, categories of
clinging's objects. These are the 5 aspects in which the Buddha has
summed up all the physical and mental phenomena of existence, and
which appear to the ignorant man as his ego, or personality.