diff --git a/cmuratori/hero/code/code440.hmml b/cmuratori/hero/code/code440.hmml
index e0de613..a66e950 100644
--- a/cmuratori/hero/code/code440.hmml
+++ b/cmuratori/hero/code/code440.hmml
@@ -1,17 +1,26 @@
 [video member=cmuratori stream_platform=twitch stream_username=handmade_hero project=code medium=speech title="Introduction to Function Approximation with Andrew Bromage" vod_platform=youtube id=0b68cEY2wKs guest=Pseudonym73 annotator=Miblo]
 [0:00][Welcome to a special episode with [@Pseudonym73 Andrew Bromage]]
-[2:42][@Pseudonym73][How floating point numbers are represented by a computer]
+[2:42][@Pseudonym73][How floating point numbers are represented by a computer[ref
+    publisher=IEEE
+    title="754-2008 - IEEE Standard for Floating-Point Arithmetic"
+    url=http://ieeexplore.ieee.org/servlet/opac?punumber=4610933]]
 [4:36][@Pseudonym73][Scientific notation, and how IEEE 754 represents numbers in binary][:mathematics :"numeral system"]
 [7:14][Get [@Pseudonym73 Andrew] back][:admin]
 [9:27][@Pseudonym73][Return]
-[10:36][@Pseudonym73][Continuing IEEE 754's representation of floating point numbers[ref
+[10:36][@Pseudonym73][Continuing IEEE 754's[ref
+    publisher=IEEE
+    title="754-2008 - IEEE Standard for Floating-Point Arithmetic"
+    url=http://ieeexplore.ieee.org/servlet/opac?punumber=4610933] representation of floating point numbers[ref
     site="Float Toy"
     url=http://evanw.github.io/float-toy/]][:mathematics :"numeral system"]
 [16:20][@Pseudonym73][Subnormal numbers, the special-case numbers infinity, quiet NaN and signaling NaN, and the quality of being "algebraically closed"][:mathematics :"numeral system"]
 [24:10][@Pseudonym73][Any questions?]
 [24:35][Is it just a peculiarity of binary as a number system, that you can skip encoding the leading digit?][:mathematics :"numeral system"]
 [26:06][@desuused][Q: Is there a representation for underflowing numbers?][:mathematics :"numeral system"]
-[27:28][@Pseudonym73][Note the binary and decimal representations of floating point numbers in the IEEE 754 standard][:mathematics :"numeral system"]
+[27:28][@Pseudonym73][Note the binary and decimal representations of floating point numbers in the IEEE 754 standard[ref
+    publisher=IEEE
+    title="754-2008 - IEEE Standard for Floating-Point Arithmetic"
+    url=http://ieeexplore.ieee.org/servlet/opac?punumber=4610933]][:mathematics :"numeral system"]
 [27:51][@Pseudonym73][Constants definitions in handmade_numerics.h][:mathematics :"numeral system" :research]
 [30:22][@Pseudonym73][Constants definitions in C's float.h[ref
     site=Wikibooks
@@ -25,9 +34,15 @@
     url=https://msdn.microsoft.com/en-us/library/w1xfschh.aspx] with an example of its use in a sqrt() function][:mathematics :"numeral system" :research]
 [47:36][When multiplying a subnormal number by a power of two, does the floating point unit first shift the numbers into the normal range before incrementing the exponent?][:mathematics :"numeral system"]
 [50:38][@Pseudonym73][Describe ScaleByExponent()][:mathematics :"numeral system" :research]
-[53:58][@Pseudonym73][Note the differing range of absolute values of the mantissa in text books (as used in handmade_numerics.h) and the CRT's frexp()][:mathematics :"numeral system" :research]
+[53:58][@Pseudonym73][Note the differing range of absolute values of the mantissa in text books (as used in handmade_numerics.h) and the CRT's frexp()[ref
+    site=MSDN
+    page=frexp
+    url=https://msdn.microsoft.com/en-us/library/w1xfschh.aspx]][:mathematics :"numeral system" :research]
 [57:01][@Pseudonym73][Quote James H. Wilkinson on the state of computer arithmetic in 1971][:mathematics :"numeral system"]
-[58:30][@Pseudonym73][Describe SlowDivision(), with emphasis on the sheer amount of specification compliance it contains][:mathematics :research]
+[58:30][@Pseudonym73][Describe SlowDivision(), with emphasis on the sheer amount of specification compliance it contains[ref
+    publisher=IEEE
+    title="754-2008 - IEEE Standard for Floating-Point Arithmetic"
+    url=http://ieeexplore.ieee.org/servlet/opac?punumber=4610933]][:mathematics :research]
 [1:06:29][@Pseudonym73][Walk through an example of SlowDivision(), noting why it uses 11 bits of precision in its application of Horner's rule[ref
     site=Wikipedia
     page="Horner's method"
@@ -63,10 +78,13 @@
 [1:56:43][@gg_nate][Can you set video / audio bit rate on hangouts? If he could lower the bit rate of the video the audio might work better]
 [1:56:57][@Pseudonym73][Describe SinCos_TableVersion()][:mathematics :research]
 [1:58:31][@Pseudonym73][Deriving trigonometric identities][:mathematics]
-[2:02:28][@Pseudonym73][Calculating cosine around "a" branch-free][:mathematics]
+[2:02:28][@Pseudonym73][Calculating cosine around "a", branch-free][:mathematics]
 [2:04:00][@Pseudonym73][Point out the experimental SinCos_QuadrantVersion() for SIMD sines and cosines][:mathematics :optimisation :research]
 [2:05:54][@Pseudonym73][Describe the XSinCosX table look up][:mathematics :research]
-[2:07:56][@Pseudonym73][Counting has always started at zero][:mathematics :"numeral system" :research]
+[2:07:56][@Pseudonym73][Counting has always started at zero[ref
+    author="Philip Wadler"
+    title="As Natural as 0, 1, 2"
+    url=https://homepages.inf.ed.ac.uk/wadler/papers/natural/natural.pdf]][:mathematics :"numeral system" :research]
 [2:08:47][@Pseudonym73][Continued description of the XSinCosX table look up][:mathematics :research]
 [2:10:38][@Pseudonym73][:Run calculate_sincos_tables and explain the result for .5][:mathematics]
 [2:12:10][@Pseudonym73][Describe how FindSinCosAround() searches adjacent floating point numbers][:mathematics :research]