[1] [CITE@en[CSS WG Blog – How to unprefix -webkit-device-pixel-ratio]]
( ([TIME[2013-07-28 14:04:13 +09:00]] 版))
<http://www.w3.org/blog/CSS/2012/06/14/unprefix-webkit-device-pixel-ratio/>

[2] webkit, moz とも値は[[非負]]の [CODE(CSS)@en[[[<number>]]]] のようです。

[3] 
[PRE(CSS example code)[
@media (-webkit-min-device-pixel-ratio: 0) {} みたいな。
]PRE]

[4] [CITE@en-US[CSS media queries - Web developer guide | MDN]]
( ([TIME[2013-09-03 09:34:26 +09:00]] 版))
<https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Media_queries#-moz-device-pixel-ratio>

[5] [CITE@en[Issue #15. Spec -webkit-device-pixel-ratio media query feature. · whatwg/compat@0ad0180]]
([TIME[2015-11-11 18:34:22 +09:00]] 版)
<https://github.com/whatwg/compat/commit/0ad018058a311e917efd6e8db3aabbb2bd468ca0>

[6] [CITE@en[Issue #15. Let's make this a MAY. Also fix typo in name. >_> · whatwg/compat@0f1e8d0]]
([TIME[2015-11-11 18:34:55 +09:00]] 版)
<https://github.com/whatwg/compat/commit/0f1e8d0513256ef6b44bd2a165799bc3318a8ade>

[7] [CITE@en[Issue #15. Attempt to properly spec out -webkit-device-pixel-ratio. · whatwg/compat@dd9c77d]]
([TIME[2015-11-14 13:15:54 +09:00]] 版)
<https://github.com/whatwg/compat/commit/dd9c77d8e80a920b31db810770a1bbdd1df46dae>

[8] [CITE@en[Fix #15: -webkit-device-pixel-radius value is <<number>> · whatwg/compat@551abca]]
([TIME[2015-11-19 16:25:42 +09:00]] 版)
<https://github.com/whatwg/compat/commit/551abcaaf545a8acda50b2dd31c4e1bb11b38e0f>