1diff --git a/README.md b/README.md
  2index 8f2e811..77ea268 100644
  3--- a/README.md
  4+++ b/README.md
  5@@ -1,5 +1,5 @@
  6 # Spreadsheet
  7-TypeScript implementation of a spreadsheet.
  8+TypeScript/javascript implementation of a spreadsheet.
  9 
 10 ## TODO
 11 Things I should do.
 12@@ -10,14 +10,6 @@ And the same for MAX, MAXA, COUNT, COUNTA, etc. Look these over.
 13 ### Criteria evaluations should escape reg-ex characters
 14 http://stackoverflow.com/questions/3446170/escape-string-for-use-in-javascript-regex
 15 
 16-### Document the functions pulled in from jStat.
 17-
 18-### Double check all relevant formulas from MSExcel and GS have been implemented.
 19-
 20-### Refactor the way tests are organized.
 21-Group by error type and have some useful functions that will call with 0, N, N+1 args to test the args
 22-checker. Also, test for *all possible* errors that could be thrown, and *all possible types* that could be passed in.
 23-Another thing to think about would be throwing custom errors if an object is passed in.
 24 
 25 ### jStat functions should know their caller
 26 Either through `arguments`, or directly passed in like `mean("FORMULA", [10, 20, 30])`
 27diff --git a/src/RawFormulas/Math.ts b/src/RawFormulas/Math.ts
 28index 3123058..335bcc3 100644
 29--- a/src/RawFormulas/Math.ts
 30+++ b/src/RawFormulas/Math.ts
 31@@ -823,7 +823,17 @@ var ERF = function (...values) : number {
 32   return values.length === 1 ? erf(lower) : erf(upper) - erf(lower);
 33 };
 34 
 35-// erf function from jStat [http://www.jstat.org/]
 36+
 37+/**
 38+ * Returns the error function evaluated at x. See also:
 39+ *
 40+ * * http://jstat.github.io/special-functions.html#erf
 41+ *
 42+ * * https://github.com/jstat/jstat/search?utf8=%E2%9C%93&q=erf&type=
 43+ *
 44+ * @param x to evaluate
 45+ * @returns {number} error
 46+ */
 47 function erf(x) {
 48   var cof = [-1.3026537197817094, 6.4196979235649026e-1, 1.9476473204185836e-2,
 49     -9.561514786808631e-3, -9.46595344482036e-4, 3.66839497852761e-4,
 50diff --git a/src/RawFormulas/Statistical.ts b/src/RawFormulas/Statistical.ts
 51index e1aeb88..70d7f15 100644
 52--- a/src/RawFormulas/Statistical.ts
 53+++ b/src/RawFormulas/Statistical.ts
 54@@ -192,15 +192,30 @@ var AVERAGEA = function (...values) {
 55  * @constructor
 56  */
 57 var CORREL = function (...values) : number {
 58+  /**
 59+   * Return the standard deviation of a vector. By defaut, the population standard deviation is returned. Passing true
 60+   * for the flag parameter returns the sample standard deviation. See http://jstat.github.io/vector.html#stdev for
 61+   * more information.
 62+   */
 63   function stdev(arr, flag) {
 64     return Math.sqrt(variance(arr, flag));
 65   }
 66+
 67+  /**
 68+   * Return the variance of a vector. By default, the population variance is calculated. Passing true as the flag
 69+   * indicates computes the sample variance instead. See http://jstat.github.io/vector.html#variance for more
 70+   * information.
 71+   */
 72   function variance(arr, flag) {
 73     if ((arr.length - (flag ? 1 : 0)) === 0) {
 74       throw new DivZeroError("Evaluation of function CORREL caused a divide by zero error.");
 75     }
 76     return sumsqerr(arr) / (arr.length - (flag ? 1 : 0));
 77   }
 78+
 79+  /**
 80+   * Return the sum of a vector. See http://jstat.github.io/vector.html#sum for more information.
 81+   */
 82   function sum(arr) {
 83     var sum = 0;
 84     var i = arr.length;
 85@@ -209,12 +224,20 @@ var CORREL = function (...values) : number {
 86     }
 87     return sum;
 88   }
 89+  /**
 90+   * Return the mean of a vector. See http://jstat.github.io/vector.html#mean for more information.
 91+   */
 92   function mean(arr) {
 93     if (arr.length === 0) {
 94       throw new DivZeroError("Evaluation of function CORREL caused a divide by zero error.");
 95     }
 96     return sum(arr) / arr.length;
 97   }
 98+
 99+  /**
100+   * Return the sum of squared errors of prediction of a vector. See http://jstat.github.io/vector.html#sumsqerr for
101+   * more information.
102+   */
103   function sumsqerr(arr) {
104     var m = mean(arr);
105     var sum = 0;
106@@ -226,6 +249,10 @@ var CORREL = function (...values) : number {
107     }
108     return sum;
109   }
110+
111+  /**
112+   * Return the covariance of two vectors. See http://jstat.github.io/vector.html#covariance for more information.
113+   */
114   function covariance(arr1, arr2) {
115     var u = mean(arr1);
116     var v = mean(arr2);
117@@ -308,6 +335,10 @@ var EXPONDIST = function (...values) : number {
118  * TODO: This function should be stricter in its return type.
119  */
120 var FDIST$LEFTTAILED = function (...values) : number|undefined|boolean {
121+  /**
122+   * Returns the Log-Gamma function evaluated at x. See http://jstat.github.io/special-functions.html#gammaln for more
123+   * information.
124+   */
125   function gammaln(x) {
126     var j = 0;
127     var cof = [
128@@ -322,6 +353,11 @@ var FDIST$LEFTTAILED = function (...values) : number|undefined|boolean {
129       ser += cof[j] / ++y;
130     return Math.log(2.5066282746310005 * ser / xx) - tmp;
131   }
132+
133+  /**
134+   * Returns the Gamma function evaluated at x. This is sometimes called the 'complete' gamma function. See
135+   * http://jstat.github.io/special-functions.html#gammafn for more information.
136+   */
137   function gammafn(x) {
138     var p = [-1.716185138865495, 24.76565080557592, -379.80425647094563,
139       629.3311553128184, 866.9662027904133, -31451.272968848367,
140@@ -369,6 +405,11 @@ var FDIST$LEFTTAILED = function (...values) : number|undefined|boolean {
141     }
142     return res;
143   }
144+
145+  /**
146+   * Returns the continued fraction for the incomplete Beta function with parameters a and b modified by Lentz's method
147+   * evaluated at x. For more information see http://jstat.github.io/special-functions.html#betacf.
148+   */
149   function betacf(x, a, b) {
150     var fpmin = 1e-30;
151     var m = 1;
152@@ -414,6 +455,11 @@ var FDIST$LEFTTAILED = function (...values) : number|undefined|boolean {
153 
154     return h;
155   }
156+
157+  /**
158+   * Returns the incomplete Beta function evaluated at (x,a,b). See http://jstat.github.io/special-functions.html#ibeta
159+   * for more information.
160+   */
161   function ibeta(x, a, b) {
162     // Factors in front of the continued fraction.
163     var bt = (x === 0 || x === 1) ?  0 :
164@@ -428,9 +474,21 @@ var FDIST$LEFTTAILED = function (...values) : number|undefined|boolean {
165     // else use continued fraction after making the symmetry transformation.
166     return 1 - bt * betacf(1 - x, b, a) / b;
167   }
168+
169+  /**
170+   * Returns the value of x in the cdf of the Gamma distribution with the parameters shape (k) and scale (theta). Notice
171+   * that if using the alpha beta convention, scale = 1/beta. For more information see
172+   * http://jstat.github.io/distributions.html#jStat.gamma.cdf
173+   */
174   function cdf(x, df1, df2) {
175     return ibeta((df1 * x) / (df1 * x + df2), df1 / 2, df2 / 2);
176   }
177+
178+  /**
179+   * Returns the value of x in the pdf of the Gamma distribution with the parameters shape (k) and scale (theta). Notice
180+   * that if using the alpha beta convention, scale = 1/beta. For more information see
181+   * http://jstat.github.io/distributions.html#jStat.gamma.pdf
182+   */
183   function pdf(x, df1, df2) {
184     if (x < 0) {
185       return undefined;
186@@ -468,9 +526,13 @@ var FDIST$LEFTTAILED = function (...values) : number|undefined|boolean {
187  * @param values[2] deg_freedom2 - Required. The denominator degrees of freedom.
188  * @returns {number} inverse of the (right-tailed) F probability distribution
189  * @constructor
190- * TODO: This function needs to be tested more thuroughly.
191+ * TODO: This function needs to be tested more thoroughly.
192  */
193 var FINV = function (...values) : number {
194+  /**
195+   * Returns the continued fraction for the incomplete Beta function with parameters a and b modified by Lentz's method
196+   * evaluated at x. For more information see http://jstat.github.io/special-functions.html#betacf
197+   */
198   function betacf(x, a, b) {
199     var fpmin = 1e-30;
200     var m = 1;
201@@ -516,6 +578,11 @@ var FINV = function (...values) : number {
202 
203     return h;
204   }
205+
206+  /**
207+   * Returns the incomplete Beta function evaluated at (x,a,b). See http://jstat.github.io/special-functions.html#ibeta
208+   * for more information.
209+   */
210   function ibeta(x, a, b) : number {
211     // Factors in front of the continued fraction.
212     var bt = (x === 0 || x === 1) ?  0 :
213@@ -532,6 +599,11 @@ var FINV = function (...values) : number {
214     // else use continued fraction after making the symmetry transformation.
215     return 1 - bt * betacf(1 - x, b, a) / b;
216   }
217+
218+  /**
219+   * Returns the Log-Gamma function evaluated at x. For more information see
220+   * http://jstat.github.io/special-functions.html#gammaln
221+   */
222   function gammaln(x) {
223     var j = 0;
224     var cof = [
225@@ -546,6 +618,11 @@ var FINV = function (...values) : number {
226       ser += cof[j] / ++y;
227     return Math.log(2.5066282746310005 * ser / xx) - tmp;
228   }
229+
230+  /**
231+   * Returns the inverse of the incomplete Beta function evaluated at (p,a,b). For more information see
232+   * http://jstat.github.io/special-functions.html#ibetainv
233+   */
234   function ibetainv(p, a, b) {
235     var EPS = 1e-8;
236     var a1 = a - 1;
237@@ -595,6 +672,10 @@ var FINV = function (...values) : number {
238     }
239     return x;
240   }
241+
242+  /**
243+   * http://jstat.github.io/distributions.html
244+   */
245   function inv(x, df1, df2) {
246     return df2 / (df1 * (1 / ibetainv(x, df1 / 2, df2 / 2) - 1));
247   }
248diff --git a/tests/StatisticalTest.ts b/tests/StatisticalTest.ts
249index 15ec9a8..6da9cd4 100644
250--- a/tests/StatisticalTest.ts
251+++ b/tests/StatisticalTest.ts
252@@ -228,6 +228,7 @@ catchAndAssertEquals(function() {
253 
254 // Test FINV
255 assertEquals(FINV(0.42, 2, 3), 1.174597274485816);
256+// TODO: Test this more.
257 
258 
259 // Test FISHER