Baillie, Robert (May 1979). "Sums of Reciprocals of Integers Missing a Given Digit". American Mathematical Monthly. 86 (5). Washington, DC: Mathematical Association of America: 372–374. doi:10.2307/2321096. ISSN0002-9890. JSTOR2321096.
"ERRATA". American Mathematical Monthly. 87 (10). Washington, DC: Mathematical Association of America: 866. December 1980. doi:10.2307/2320815. ISSN0002-9890. JSTOR2320815.
Irwin, Frank (May 1916). "A Curious Convergent Series". American Mathematical Monthly. 23 (5). Washington, DC: Mathematical Association of America: 149–152. doi:10.2307/2974352. ISSN0002-9890. JSTOR2974352.
Baillie, Robert (May 1979). "Sums of Reciprocals of Integers Missing a Given Digit". American Mathematical Monthly. 86 (5). Washington, DC: Mathematical Association of America: 372–374. doi:10.2307/2321096. ISSN0002-9890. JSTOR2321096.
"ERRATA". American Mathematical Monthly. 87 (10). Washington, DC: Mathematical Association of America: 866. December 1980. doi:10.2307/2320815. ISSN0002-9890. JSTOR2320815.
Irwin, Frank (May 1916). "A Curious Convergent Series". American Mathematical Monthly. 23 (5). Washington, DC: Mathematical Association of America: 149–152. doi:10.2307/2974352. ISSN0002-9890. JSTOR2974352.
Baillie, Robert (May 1979). "Sums of Reciprocals of Integers Missing a Given Digit". American Mathematical Monthly. 86 (5). Washington, DC: Mathematical Association of America: 372–374. doi:10.2307/2321096. ISSN0002-9890. JSTOR2321096.
"ERRATA". American Mathematical Monthly. 87 (10). Washington, DC: Mathematical Association of America: 866. December 1980. doi:10.2307/2320815. ISSN0002-9890. JSTOR2320815.
Irwin, Frank (May 1916). "A Curious Convergent Series". American Mathematical Monthly. 23 (5). Washington, DC: Mathematical Association of America: 149–152. doi:10.2307/2974352. ISSN0002-9890. JSTOR2974352.